The murmurs in the stands began as soon as the duo began their walk out on court. Fans commented on the disparity in height between the two, some whispering that one was not even as tall as the net between the players.

China's Sun Yu, the world No. 14, is not ranked as high as No. 4 Nozomi Okuhara of Japan. But towering at 1.83m, she outpowered her opponent to ensure she could at least use her height to her advantage.

Using her reach to send Okuhara scrambling around the court, Sun posted a 21-16, 21-11 win yesterday at the OUE Singapore Open to eliminate the tournament's second seed.

Said the defending champion, who was 3-3 against Okuhara before yesterday's tie: "We've split wins and losses in the past. I put a lot of work into preparation for this match and I think that paid off.

"To me, what made a greater difference today was that I came into the match very determined and knew what I had to do strategically."

Sun will play South Korean Sung Ji Hyun today in the quarter-finals.

Okuhara lauded her opponent for coming prepared. Said this year's All England Open champion, who stands at 1.55m: "I usually hit low shots to tall players like Sun Yu to annoy them, but she came ready for that so it was difficult to beat her.

"I do feel a little disappointed over the loss but it's the whole process that matters. I've had serious knee injuries in the past and my focus is on working on my mobility.

"The next step is to return to Japan, continue to practise and do better next time."

Two-time champion and world No. 6 Wang Yihan was also beaten 9-21, 24-22, 21-17 by Thailand's Porntip Buranaprasertsuk.

Said the Thai world No. 19: "My opponent was controlling me at the back of the court in the first game and I wasn't really able to attack, but after we changed ends the draught was more to my advantage."

She earns a quarter-final meeting with team-mate and world No. 2 Ratchanok Intanon.

In the men's singles, a second comeback win in a row gave China's world No. 1 Chen Long a 17-21, 21-18, 21-9 victory over Thailand's Boonsak Ponsana, the Singapore Open's most successful player with two titles and three runner-up finishes.

In a buoyant mood after earning his first quarter-final berth in three attempts here, Chen said: "Boonsak is a veteran player and has always done well in Singapore. I told myself it doesn't matter if I'm not the champion. I just want to beat the guy who has done the best here."

But on a more serious note, Chen said finally making the final eight does not mean he will not take his foot off the pedal.

"It was still a hard-fought victory. I still made far too many cheap mistakes. It wasn't easy getting to the quarter-finals and there are a lot of fans who come to support me so I'm going to take one match at a time."

Team-mate Lin Dan easily won his match against Indonesia's Jonatan Christie 21-13, 21-7.

He will play 2013 champion Tommy Sugiarto of Indonesia today.