The Serbian world number one looked in ominous form at the O2 Arena as he looks to finish his season with a flourish, winning 6-4, 6-3 in a focused and disciplined display.

In stark contrast to second seed Roger Federer, who produced an error-strewn performance in defeat to Kei Nishikori on Sunday, Djokovic hit just six unforced errors and won 86 percent of points on his serve.

He broke the giant Isner in the fifth game of the first set to establish a stranglehold on the match and never looked like allowing the American back into the contest, breaking twice more in the second set to win in 73 minutes.

“The match was great, obviously,” said Djokovic. “I had three breaks of serve of John which is sometimes ‘mission impossible’ but I managed to be at the right place at the right time.

“I held serve well, I backed it up from the baseline, I played very solid and didn’t give him many opportunities.”

Earlier, Zverev kept his nerve at the key moments to beat Marin Cilic 7-6 (7/5), 7-6 (7/1).

In a contest packed with unforced errors, the 21-year-old third seed recovered from a break down in each set to establish an early foothold in the Guga Kuerten group.

The 30-year-old Cilic, who has a reputation for faltering when under intense pressure, broke first but Zverev hit back as he served for the set at 5-3, going on to edge the tie-break.

In the second set, Cilic again drew first blood, breaking Zverev in the seventh game to establish a 4-3 lead but the German responded immediately to level at 4-4.

Cilic, seeded fifth in London, dug deep to save match point when trailing 4-5 but the set went to another tie-break, which Zverev dominated, winning 7/1 to seal the match.

– Error count –

There were a total of 78 unforced errors in the contest — with Cilic hitting 46 of those — as both players struggled to adapt to the court conditions.

“The court is difficult,” said Zverev. “The court is very fast. And it’s very high-bouncing as well. So, it’s more difficult than in other tournaments, so everybody has to kind of find their rhythm in the first match.

“But at the end of the day it was a pretty good match. I’m happy to get the win. That’s the most important thing. It’s important — this tournament is big. It is very important to all of us players.”

Zverev has long been talked about as one of the brightest talents of his generation and will be keen to make a statement in London after again flattering to deceive at Grand Slam level this season.

Federer lost to Nishikori in straight sets in the Lleyton Hewitt group on Sunday, leaving him in grave danger of failing to qualify for the semi-finals for only the second time in his career.

The ATP Finals are contested by the eight players who have accumulated the most ranking points over the season and is in a round-robin format, with the best four players reaching the knockout semi-finals stage.

The FA said the allegations related to events that took place in January of this year.

Sturridge is alleged to have broken rules that prohibit the passing on of information about players, managers, team selection or disciplinary matters not publicly available at the time.

The 29-year-old has until 6:00pm local time (1800 GMT) on November 20 to respond to the charges.

It is alleged he specifically contravened FA Rule E8(1)(a)(ii) and Rule E8(1)(b).

The first says “a participant” must not bet either directly or indirectly, by instructing someone else to bet on any aspect of a football match or competition or “any other matter concerning or related to football anywhere in the world”.

The second of these rules cautions against the passing on of ‘inside information’ for betting purposes.

A Liverpool spokesman, quoted by the BBC, said: “Daniel has given his full and unequivocal co-operation throughout this process and has assured the club he will continue to do so.

“Daniel has also stated categorically that he has never gambled on football.”

The spokesman added: “As with any issue of this nature, we will allow the process to be concluded in its entirety before making any further comment.”

Sturridge, who joined Liverpool from Chelsea in 2013, spent the second half of last season at West Bromwich Albion after moving on loan on January 29.

He won the last of his 26 England caps against Lithuania in October 2017.

2018 has broken records, tested limits, reset the boundaries and rewritten some history. We end the season with a seven-time World Champion, some of the closest races and podiums in history, and another incredible highlights reel of this spectacular season. But it’s not over yet – there’s one more weekend to race.

Marc Marquez (Repsol Honda Team) likely arrives as the favourite. The reigning Champion took an impressive win at Sepang to bounce back in style, and he arrives as the home hero in form. Marquez also has a good record at Valencia – wrapping up two MotoGP™ crowns there since 2013, and winning from the back in Moto2™ – and he’ll want to win again on home turf to cement his stellar season. This year, however, there may well be more eyes on the other side of the Repsol Honda box at the season finale, with teammate Dani Pedrosa yes, having a great record there and yes, back on song at Sepang, but more importantly the three-time World Champion will be hanging up his leathers at the end of the season – in terms of competition at least. After a career competing with Honda and marking some incredible achievements, Pedrosa retires from active race duty after Valencia and will become a KTM test rider. On Thursday he will also become a MotoGP™ Legend as he’s inducted into the Hall of Fame.

Maverick Viñales (Movistar Yamaha MotoGP) is another home hero aiming high. After winning in Australia, Sepang was a tougher qualifying in difficult conditions that hampered the Spaniard slightly on race day, but Yamaha seem to be back in the fight at the front. He’ll want another win to end the season and his teammate Valentino Rossi, who came so close at Sepang, will want to win his first race of the year. Rossi’s incredible laptimes in Malaysia only came undone a handful of laps from the end, and although Valencia is traditionally a more difficult track for the ‘Doctor’, he was on fire at Sepang.

For the Ducati Team Valencia has also been a more difficult track at times. Last season didn’t quite put paid to that either as both men crashed out, but Jorge Lorenzo especially has an incredible record at the Circuit Ricardo Tormo. He is determined to make it through the whole weekend this time and make his return from injury, and although he may well not be able to hammer home the kind of pace he’s previously shown at the venue, he can’t be counted out altogether. For teammate Andrea Dovizioso it’s sometimes been a more difficult venue but some incredible battles in the past mean ‘DesmoDovi’ can’t be counted out. On the podium at Phillip Island to underline the incredible progress made by the Borgo Panigale factory at every different type of track, Dovizioso has second in the Championship wrapped up and will have a few points to prove in the last race of the year.

Team Suzuki Ecstar, meanwhile, are on form. Andrea Iannone has been on it despite a twitchy crash behind Marquez in Malaysia, and it’s his last race for the Hamamatsu factory. And Alex Rins showed once again last time out quite how competitive Suzuki now are as he took that stunning second place and equaled his best result in the premier class. Rins is on home turf and on a roll and can’t be counted out.

The man he beat to second at Sepang was Johann Zarco (Monster Yamaha Tech 3) as the Frenchman got back on the podium – and from pole after Marquez was penalised. After Zarco and Danilo Petrucci (Alma Pramac Racing) were both given the opportunity to make big gains on the injured Cal Crutchlow (LCR Honda Castrol) in Australia in the fight for top Independent Team rider and neither could, Malaysia was Zarco staking a serious claim on that title. The 16 points for third put him one point above Crutchlow and five clear of Petrucci – with his form last season at Valencia marking him as the favourite to outrace the rest. Rookie of the Year is also on the line, with Franco Morbidelli (EG 0,0 Marc VDS) looking to wrap that up.

At Aprilia Racing Team Gresini, Aleix Espargaro races at home and they bid goodbye to Scott Redding after the race weekend, with Red Bull KTM Factory Racing aiming to stay ahead of the Noale factory. KTM are two points clear as a constructor and a handful more as a team so there’s everything to race for – before they also begin a new era.

The 2018 chapter of the incredible story of the MotoGP™ World Championship draws to a close at Valencia, but the final race weekend of the season is far from an epilogue. The unique atmosphere of the amphitheater setting always makes it a race weekend to remember – and this time, that’s even more true than ever. Goodbyes and new beginnings start here – from the 16th to 18th November.

Championship Standings

1 – Marc Marquez (SPA) HONDA 321 points

2 – Andrea Dovizioso (ITA) DUCATI 220

3 – Valentino Rossi (ITA) YAMAHA 195

4 – Maverick Viñales (SPA) YAMAHA 193

5 – Alex Rins (SPA) SUZUKI 149