The 20-year-old right winger — who has had more playing time in the Champions League this term than the Bundesliga as coach Lucien Favre generally prefers England international Jadon Sancho in that position — has been loaned back to the German league leaders until the end of the season.

“In the summer I move on to Chelsea and to a new competition, the English Premier League,” Pulisic said in a statement issued by Chelsea.

“It’s a privilege to have signed for such a legendary club and I look forward to working hard towards being a contributor to their team of world class players.”

Chelsea director Marina Granovskaia said she looked forward to Pulisic becoming a major influence at the club for years to come.

“We are delighted to have signed one of Europe’s most sought-after young players,” she said.

“Christian has shown his quality during a fantastic spell in Germany and at just 20, we believe he has the potential to become an important Chelsea player for many years to come.”

Michael Zorc, Dortmund’s sport director, said given the size of the offer the club would have been foolish to turn it down.

“It has always been Christian’s big dream to play in the Premier League,” said Zorc.

“That’s certainly got to do with his American background, and therefore we were unable to extend his contract.

“With this background and given the short remaining period on his contract, we decided to accept the extraordinarily lucrative offer from FC Chelsea.”

Pulisic, who had also been linked with Premier League leaders Liverpool, has been at Dortmund since he was 15 and aged just 17 made both his Bundesliga debut and international debut for the United States having turned down an approach from Crotia to play for them.

A former national Under-17 captain, in November 2018 he became the youngest player to captain the United States senior side aged 20 years and 63 days.

Nadal, who had a first round bye, was scheduled to play his second round match against Frenchman Jo-Wilfried Tsonga on Thursday.

However, after conferring with his doctors he decided to withdraw to ensure he would be fit to play the Australian Open later this month.

Nadal, the current world number two, has not played a main tour event since a knee problem forced him to retire during his US Open semi-final against Juan Martin del Potro in September.

The 32-year-old had surgery on his ankle in November to remove a loose intra-articular body and only resumed training three weeks ago.

He played the opening round at an exhibition event in Abu Dhabi last week, where he lost to South African Kevin Anderson.

“I feel good, but after a long period of time without competing, I felt the leg tightening a little bit in Abu Dhabi in the first match,” he said.

“That’s why I didn’t play the second (match). So I came here. I did an MRI, and it shows a very small strain on the left thigh, but it’s there.”

Nadal said doctors were confident he would be fit to play in Melbourne.

“They say that it’s a very small thing, but it can become a big thing, because a strain in the muscle is dangerous,” he said.

“When you increase the intensity on the muscle when competing, then there is a big risk to make it something bigger.

“Today it’s not big. I feel better than four days ago. Probably I’m 100 per cent in five days. And then I have plenty of time to prepare for Melbourne.”

Holders Australia, four-time winners Japan, Carlos Queiroz’s Iran and hosts the United Arab Emirates are all formidable opponents, but none will relish facing Paulo Bento’s Koreans.

The 2015 runners-up have put their stamp on the international scene in recent times, stunning holders Germany at last year’s World Cup before winning the Asian Games football tournament in September.

Son, 26, was at the heart of both successes and his delight was plain to see at the Asian Games in Indonesia, where victory earned the team an exemption from South Korea’s compulsory, 21-month military service.

The Tottenham Hotspur forward, who has a deadly shot with either foot, has been in scorching form for his club, scoring seven goals in his last seven Premier League games. But he will sit out South Korea’s first two games next week under a deal with his club in return for his release for last year’s Asian Games.

Son, the most prolific Asian in Premier League history, will hope South Korea get the job done against the Philippines and Kyrgyzstan before he jets in for their final Group C clash against China on January 16.

The Koreans, edged 2-1 by Australia after the 2015 final went to extra time, haven’t won the Asian Cup since 1960 — a puzzling record considering their 10 World Cup appearances, including the 2002 semi-finals.

– Arnold’s predicament –

Japan are among their chief rivals in UAE, after they were the only Asian side to reach the World Cup knock-outs before narrowly going down to Belgium in the last 16.

The Blue Samurai, winners of four of the last seven editions, will demand improvements on 2015, when as defending champions they slipped up with a penalties defeat to UAE in the last eight.

Recent results have been encouraging, including a 4-3 win over Uruguay, and Hajime Moriyasu has picked on form after ditching World Cup stars Shinji Kagawa and Shinji Okazaki in favour of younger players.

Australia, however, seem to have gone backwards since they lifted the trophy in Sydney in 2015, and it’s a tall order for new coach Graham Arnold who is plunged into the title defence just four games into the job.

After record scorer Tim Cahill retired, Arnold’s predicament worsened last month when midfield lynchpin Aaron Mooy suffered a serious knee injury and was ruled out of tournament.

Three-time winners Iran look much more settled, and after winning plaudits for their narrow 1-0 defeat to Spain and 1-1 draw with Portugal at the World Cup, Carlos Queiroz’s side have gone unbeaten in their six games since.

With attacking talent including Rubin Kazan’s Sardar Azmoun, with 24 goals in 40 internationals, and Brighton winger Alireza Jahanbakhsh, Iran will expect to do better than 2015, when they were ousted in a combustible quarter-final against arch-rivals Iraq.

– Dark horses and VAR –

UAE received a body blow with the loss of playmaker Omar Abdulrahman to a knee injury, but they have plenty of firepower and are redoubtable on home ground, where they were runners-up as hosts in 1996.

Meanwhile, rivals Qatar are desperate to make a statement before 2022, when they will be the first World Cup hosts in the modern era never to have qualified for the tournament by right.

Success in UAE would be doubly satisfying for Qatar, who have been at the centre of a diplomatic storm in the Gulf and under blockade from their neighbours since June 2017.

On Saturday in Abu Dhabi, the UAE and Bahrain will open the biggest Asian Cup yet after it grew from 16 to 24 teams, paving the way for Kyrgyzstan, war-torn Yemen and Sven-Goran Eriksson’s Philippines to make their debuts.

Among many sub-plots, China’s stuttering attempts to become a football power will come under scrutiny, in what looks set to be Marcello Lippi’s last outing as coach, while India get a rare chance to impress at the region’s top level.

Saudi Arabia, who won the last of their three Asian Cup titles in 1996, should factor in the closing stages, and Syria, Uzbekistan and North Korea lurk as dark horses.

One wildcard looks set to be the introduction of video assistant referees (VAR) from the quarter-finals, which could raise the likelihood of penalties after playing a role in the record number given at last year’s World Cup.

Kane’s third-minute opening goal is the fifth successive New Year’s Day he has scored in the Premier League, equalling a record held by Andy Cole and Steven Gerrard.

Christian Eriksen and Son Heung-Min added further goals as Spurs had the win wrapped up before half-time and reclaimed second place, a point above Manchester City, and six behind leaders Liverpool.

This performance marked Mauricio Pochettino’s side out as still being live title contenders and a stark contrast to the limp way they lost to another promoted side Wolverhampton Wanderers at home on Saturday.

They toyed with Cardiff at times, and the third goal killed the game, with the ‘Ole’ chants going up from the visiting fans after half an hour.

Cardiff’s poor record against the top teams continued, losing their last 15 Premier League matches against the ‘big six’ sides, conceding 45 goals.

The Bluebirds had picked up four points from their last two games and recorded back-to-back clean sheets after leaking five to Manchester United in their previous home game, but any hopes of making it three quickly disappeared.

Kane’s goal came off his shin, deflecting in a loose ball from a terrible touch from Cardiff captain Sean Morrison after Kieran Trippier’s cross from the right initially hit the England captain.

The England striker has now scored 16 goals in his last 12 Premier League away matches against newly-promoted teams.

Spurs made it 2-0 after just 12 minutes with a classy goal from Eriksen.

The Danish midfielder bought himself time and space by dummying Bruno Ecuele Manga and Harry Arter before picking his spot from the edge of the box to top off an impressive move involving Moussa Sissoko and Son.

Son made it 3-0 with another stylish finish, the South Korean delaying his shot from Kane’s short pass while Morrison dallied before steering an acute-angled drive across Neil Etheridge and into the far bottom corner for his 11th goal of the season, all scored in the last 16 games.

The arrival of Junior Hoilett as a half-time substitute at least ensured Cardiff gave Spurs something to think about in the second half.

The winger forced two saves from Hugo Lloris, first with a far post header which brought a diving stop and later with a cross that was tipped over.

Cardiff suffered more problems in the 59th minute when Victor Camarasa — scorer of a superb winner against Leicester on Saturday — limped off injured to be replaced by Joe Ralls.

Spurs on the other hand looked full of goals and Kane threatened again just after the hour when he flashed an angled, rising drive wide following a pass from Dele Alli.

Then Son was denied by Etheridge after Kane put him through on goal.

Cardiff never gave up and Lloris smothered a header from Aron Gunnarssson, but there was no doubting Spurs’ superior quality.

The world number one showed he was intent on taking his form from last season into the new year with a totally dominant display against the Bosnian world number 47.

“It’s fantastic to be back and to start off the tournament like I have done makes me very confident and very happy,” said the Serb.

He added: “Results-wise and time-wise it did look quite comfortable (but) I don’t think it’s nice and fair to say it’s easy because I have respect for Dzumhur.”

Djokovic, who has won the last two Grand Slams — at Wimbledon and the US Open to take his majors total to 14 — completed the match in under an hour by predictably converting his first match point.

The 31-year-old, who has made it clear he wants to match or better Roger Federer’s record of 20 Grand Slams, was untroubled throughout.

Djokovic said he hoped that news of his comfortable victory in Doha “travels” to his rivals around the world.

“You do follow, especially what your top rivals are doing, who are they playing, watch highlights,” he said.

Djokovic’s record in Doha is now 13 wins and just one defeat and his path to a potential third title in four years — playing in Qatar is an established part of his warm-up for the Australian Open — was helped by results elsewhere as the two other highest ranking seeds were defeated at the first hurdle.

Austria’s Dominic Thiem, the number two seed, was surprisingly beaten by the world number 55, France’s Pierre Hugues-Herbert, 6-3, 7-5 in the last match on Tuesday.

And Djokovic’s Doha stroll on centre court followed a high quality match between veteran Stan Wawrinka and rising star Karen Khachanov.

The Swiss three-time Grand Slam winner won 7-6 (9/7), 6-4 to claim a notable scalp against the powerful Russian.

Khachanov, the third seed, finished last season ranked at a career-time high of number 11 and was the man who ended Djokovic’s 22-match winning streak in Paris.

He is many people’s tip to push through and challenge the established stars.

However, Khachanov had no answer to an inspired Wawrinka, currently ranked 66th in the world, as he returns from a serious knee injury.

“Today was a great match, a great level,” said Wawrinka, who has suffered an injury-plagued last two seasons.

Wawrinka and Djokovic could meet at the semi-final stage in Doha.

Another player returning from injury, Belgium’s David Goffin, the sixth seed, was beaten by Lithuanian qualifier Ricardis Berankis, 3-6, 6-4, 7-6 (7/4).

But in their very first game of 2019, City already find themselves in must-win territory to haul Liverpool back into view by inflicting the leaders’ first defeat of the season and cutting a seven-point lead to four at the Etihad on Thursday.

“With the position of Liverpool, if we drop points then it is over, it is finished; it would be almost impossible,” said Guardiola after Sunday’s 3-1 win at Southampton.

Guardiola’s obsession with Liverpool and Klopp in particular is not surprising. For a serial winner, no side and no manager has caused the Catalan as many problems as the German.

City have won just one of seven meetings since Guardiola joined Klopp in England after locking horns in charge of Bundesliga giants Bayern Munich and Borussia Dortmund.

A shock run of three defeats in four Premier League games in December has left City playing catch up to a Liverpool side eyeing history by ending a 29-year wait to win the league.

But even when seemingly no one else could stop City as they stormed to the title with a record 100 points last season, Klopp’s men were a constant menace.

– ‘They scare me’ –

Last January, it was City who were on course to equal Arsenal’s ‘Invincibles’ of 2003-04 until they went to Anfield in January and were blown away by a three-goal salvo in nine second-half minutes to lose 4-3 despite a late rally.

In the documentary “All Or Nothing” which chronicled City’s title triumph, Guardiola is seen admitting to his coaching staff ahead of returning to Anfield for the Champions League quarter-final, first leg: “They scare me. They’re dangerous, I mean it.”

It takes a lot to frighten a coach who has won 24 trophies in three different countries, but Guardiola’s fears were realised as another Liverpool blitz secured a 3-0 win.

Six days later, Liverpool won again at the Etihad, withstanding a City onslaught for 45 minutes to take control in the second period once Guardiola had lost his cool and been sent to the stands.

Now Liverpool have extended that ability for short destructive bursts into a title challenge for the long haul.

The addition of Brazilian goalkeeper Alisson Becker and a first full season with the world’s most expensive defender Virgil van Dijk has seen Klopp’s men concede just eight times in 20 Premier League games.

And after a slow start, the prolific front three of Mohamed Salah, Roberto Firmino and Sadio Mane that terrorised City last season are beginning to hit top form once more.

All three scored in the same Premier League game for the first time this season on Saturday as Arsenal were blown away 5-1 at Anfield.

“Unfortunately we lost two (games) and have a rival that is the best team in Europe or in the world in top form like Liverpool,” added Guardiola.

“That’s why it is a challenge for us next Thursday to try and win there to try and sustain this position as long as possible to arrive at the end of the season fighting for the title.”

However, the City boss has also been keen to reiterate just how good his own side are, despite their recent blip.

Until mid-December City were heavy favourites to back up a record 100-point season that saw them compared to the greatest sides English football has seen with another significant landmark of becoming the first side in a decade to retain the Premier League.

Consistent success is the mark of a truly great side and if City should reel in a Liverpool side seemingly hell bent on making history, that is a tag they will deserve.

The 32-year-old defender is pumped up about playing for the first time in the continent’s biggest football tournament, which will also feature regional heavyweights Japan, South Korea, Iran and Australia.

“Every team is stronger than we are in this tournament,” said the Nakhon Ratchasima FC’s player, who skippered the national side at last month’s AFF Suzuki Cup.

“But we have no fear. On the contrary, we are hungrier to compete and try to win. We want to see what level we are at in Asia.”

Thailand are currently training in Abu Dhabi and will launch their campaign in Group A against India on Sunday.

Chalermpong believes the War Elephants can survive the group stage, which also includes Bahrain and hosts UAE, if they play to the best of their ability.

“The tournament is a tough test for us,” added the man from Lop Buri province. “But if we can stick to the tactics of the coach [Milovan Rajevac] and play decent games, we can reach the round of 16.”

Chalermpong’s confidence is partly due to the return of the “three musketeers” – Chanathip Songkrasin, Teerasil Dangda (captain) and Teerathon Bunmathan (vice captain) – after they had to skip the AFF event due to their J-League commitments.

“There is a great deal of change in terms of the players. Having those three players from the J-League will make us stronger. We are trying to adjusting ourselves to make the most well-organised team ever,” added Chalermpong.

“What we need to do now is to focus on ourselves, not worry about the other teams. As long as we are best prepared, it will be easier for us once we are on the pitch.”

Thailand will have their final warm-up, a game against Oman behind closed doors on Wednesday before embarking on their first Asian Cup campaign in 12 years on Sunday.

The top two countries from each of the six groups, plus the four best third-placed teams, will make it into the round of 16.

The current world number two has not played a main tour event since a knee problem forced him to retire during his US Open semi-final against Juan Martin del Potro in September.

The 32-year-old had surgery on his ankle in November to remove a loose intra-articular body and only resumed training three weeks ago.

He played the opening round at an exhibition event in Abu Dhabi last week, where he lost to South African Kevin Anderson, and gets his season proper under way in the second round of the Brisbane International on Thursday.

The 17-time Grand Slam winner said he hadn’t been worried about the world rankings for the past two years.

“My goal is just to be happy doing what I am doing and be competitive all the weeks that I am playing,” he said.

“I want to feel myself competitive every week that I am on court and I want to keep fighting for the things that really make me feel alive, you know, for the things that motivate me.

“So I will not (chase) the number one because it’s not my main goal.

“Of course, I prefer to be number one than number two, and I prefer to be number two than number five, that’s obvious,” he added.

Nadal was forced to retire during matches at two of the four Grand Slams in 2018, but still added a record-extending 11th French Open crown to his collection.

He said he wanted to ensure he could take care of his body to allow him to keep playing as long as possible because of his love for the game.

“The thing that I don’t want to do is suffer more than what I did last year, because if you do (suffer injuries two) years in a row, that mentally kills you,” he said.

“I really believe that I have to keep having tennis to play in my career, and I really feel that my body is not going to get worse every year.

“Really my only goal is to keep doing the things that makes me happy, and today playing tennis makes me happy, and I want to do it the best way possible and as long as possible.”

In the second round Nadal will play either Jo-Wilfried Tsonga of France or local hope Thanasi Kokkinakis, two players who have also been troubled recently by injuries.

Revenue rose 22.7 percent on the previous season thanks in large part to a profit on player sales of £113 million and a run to the Champions League last 16 which boosted TV income by £47.1 million.

Commercial revenue was up £32 million, helped by a new Nike kit deal worth a reported £60 million a year, while matchday revenues also increased by £8.4 million.

“The club has now posted a series of record-breaking revenue figures and our profit margin has increased in consecutive years,” said chairman Bruce Buck in a statement.

“This has occurred against a backdrop of varying participation in European football, and different degrees of achievement in the Premier League, which demonstrates we have built a sound business footing to support our on-pitch quest for success.”

The latest figures for the season ending June 30, 2018 include the sales of Diego Costa to Atletico Madrid, Nemanja Matic to Manchester United, Nathan Ake to Bournemouth and the permanent transfer of Juan Cuadrado to Juventus.

However, the accounts do not include the severance pay for Antonio Conte or his coaching staff.

Conte was sacked in July after the Blues’ finished fifth and failed to qualify for this season’s Champions League.

Writing on Twitter, the Argentine said: “Recovery is going great and I will tell you later where I will be making my comeback. Unfortunately it won’t happen in Australia.”

The injury-plagued 30-year-old hobbled out of the Shanghai Masters two months ago after an awkward fall before doctors diagnosed him with a fractured patella bone in his right knee.

Since winning the US Open in 2009 as a 20-year-old, Del Potro has been plagued with physical problems, including a series of wrist injuries that required four surgeries.

But 2018 had seen something of a resurgence from a player who dropped to 581 in the world in 2015.

He beat Swiss great Roger Federer in the Indian Wells Masters final in March and in September he reached a second Grand Slam final, but was beaten in straight sets by current world No.1 Novak Djokovic at the US Open.

He even reached a career-high ranking of three in August.

While he said on Twitter he would “miss” the Australian Open, he added that he was “happy with my progress.”