World No 1 Lee Chong Wei bounced back from his first day scare, reasserting a challenge for the All-England Open title and confirming he will try once more for an Olympic gold medal.

The twice former champion from Malaysia reached the quarter-finals with a straight games win over Wang Zhengming, which was very different from the match point crises he had to survive the previous day against Hong Kong's Wang Wing-ki.

"It made me much more focussed," Lee said after his 21-17, 21-19 win over the world No 19 from China.

"I know I am very lucky still to be in the tournament. I feel very happy now that I have got through. I feel my fitness is OK and I definitely played better than yesterday."

Despite this Lee still had to come from 10-13 down in the first game and to fend off a Wang fightback which cut a five-point deficit to one near the end of the second game.

Lee produced some tremendous mid-court plunges in defense, was clever and quick at the net, and changed containment into offense fluidly with his light movement.

LEE CHONG WEI: WORLD NO 1 BADMINTON PLAYER

"I am fortunate to be here and I will just enjoy it and see," he said when asked about the All-England title, but conspicuously he did not completely refuse talk about the Olympic title in Rio de Janeiro in 2016.

"I will try for two years and see how I am," the 30-year-old said, half smiling, unable entirely to hide his pleasure at the thought.

"If I am then free of injury I will try for that."

Lee may enjoy the rest of this week as he has none of the leading players left in his half of the draw, while the prospect of an all-Chinese semifinal in the bottom half came closer.

Chen Long, the world No 2, improved the Chinese mood with a good win and some encouraging comments, which were particularly welcome after two leading Chinese players were beaten in the men's and women's singles.

Chen's lively movement and increasing maturity underlined him as a serious title contender, helping him to a 21-15, 21-10 success over Takuma Ueda, the world No 22 from Japan. He also had an explanation for the Chinese setbacks.

"Quite a lot of our squad have had to fly from Asia to Europe and are probably jetlagged, which may be why they didn't show their best form," said Chen, who saw teammates Du Pengyu, the third seed, and Hu Yun, the sixth seed, fall at the first hurdle.

Meanwhile, Tine Baun, the former world No 1 from Denmark, kept her career going for at least one more day when she came from 13-17 down in the second game to win 21-13, 22-20 against Li Han, the rising world No 15 from China.

"I was mentally clear and knew what to do, and it meant a lot to me, to hope to buy one more day," said the 33-year-old who is playing her last tournament before retirement.

Certain to have a quarter-final with an unseeded player, two-time champion Baun now looks capable of making the semis or even the final.