The former World Junior No 1, who just reached the quarter-finals in the US Open a few weeks ago, put up a gutsy fight to upset the world No 5 in 48 minutes.

“I’m so happy to beat Chen Long as he is the Olympic champion. I stuck to my attacking game and it worked,” said the 19-year-old Kantaphon.

The win over Chen was his second major upset this year after he knocked out another Olympic gold medalist Lin Dan of China 21-15 21-19 in the February’s Indonesia Open.

“Beating Chen Long and Lin Dan in the same year really gives me a lot of confidence. It proves that all the hard work paid off.”

However the 19-year-old Thai will have another tough assignment waiting him in round two as he is to face Indonesian world No 24 Tommy Sugiarto who ousted him in straight games 21-17 21-11 in the Thailand Masters final last year.

Former Thai No 1 Tanongsak Saensomboonsuk, playing his first match in several months, beat Anders Antonsen of Denmark 21-14 21-15. But SEA Games silver medalist Khosit Phetpradab, the current Thai No 1, was sent packing by world No 1 Viktor Axelsen of Denmark 17-21 21-18 13-21.

Ratchanok Intanon 

On the women’s side, Ratchanok Intanon shrugged off a sluggish start to beat Mia Blichfeldt of Denmark 21-19 21-12. Nitchaon Jindapol beat Evgeniya Kosetskaya of Russia 21-11 21-15 while Pornpawee Chochuwong moved past Line Hojmark Kjaersfeldt of Denmark 21-16 21-10.

Nitchaon Jindapol