Saina Nehwal became the biggest women's casualty when she fell in three sets to world number 10 Cheng Shao-Chieh of Taiwan in a day of carnage, that saw top men's seed Taufik Hidayat crashing out and women's world champion Wang Lin departing in tears, at the Singapore Open badminton tournament on Thursday.

Indian fourth seed Saina Nehwal became the biggest women's casualty when she fell in three sets to world number 10 Cheng Shao-Chieh of Taiwan.

Nehwal, whose successes have boosted badminton in her giant home country, looked to have Cheng's number when she romped to a one-set lead.

But the Taiwanese reeled off 13 consecutive points in the second before closing it out 8-21, 21-10, 21-19.

However, the day's worst heartache was reserved for Wang Lin, whose Olympic dream may be over after a recurrence of a serious knee injury which had kept her sidelined for seven months.

Wang, who was on the comeback trail after anterior cruciate surgery, was 12-8 down to top-seeded compatriot Wang Shixian in the tournament's second round when she abruptly pulled out.

Singapore Open officials said Wang had aggravated her damaged left knee and requested hospital treatment. If the knee has broken down, it almost certainly puts paid to her hopes of reaching next year's London Games.

The 22-year-old was crowned world champion in Paris last August but dramatically fell to earth when she suffered the career-threatening injury in her very next match, in round one of the China Masters.

Wang returned to action in April and has clawed her way back from 103 to 64 in the world, saying the thought of next year's Olympics was what drove her comeback.

"It is every athlete's dream to compete at the Olympics," she told the Straits Times this week.

But Wang will have to be among the top three players in fiercely competitive China to realise her ambition, with compatriots Wang Shixian, Wang Xin and Wang Yihan already heading the world rankings.

In other results, Chinese great Lin Dan cruised into the quarter-finals, meaning he is assured of leading the standings in this year's Super Series -- the only major honour to elude him.

The idolised "Super Dan" will next play Indonesia's Simon Santoso ahead of a likely semi-final against long-time rival Peter Gade of Denmark.

Singapore is the fifth stop on the 12-leg Super Series tour, with the top eight men, women and doubles pairs reaching the finals in December.

Meanwhile, Hidayat, the 2004 Olympic gold medallist and a two-time Singapore winner, led a parade of seeds out of the men's draw when he was shocked by China's up-and-coming Wang Zhengming, 21.

World junior champion Viktor Axelsen stunned his idol, China's Bao Chunlai, while South Korea's Lee Hyun-Il sent third seed Chen Long packing and eighth seed Park Sung-Hwan was humbled by China's Chen Jin.

Hidayat fought back from a set down against Wang but his defence proved unable to cope with the heavy-hitting Chinese, who ran away with the decider to take it 21-16, 20-22, 21-13.

The upset ends a stormy tournament for the volatile Hidayat, who had slammed Indonesian media coverage after he did not attend a pre-tournament press conference.

"Today I played very badly," he said afterwards. "I think tomorrow I'll go back to Indonesia and prepare for (next week's) Indonesian Super Series."