Top seeded Lee, who won a gold medal on December 8 with South Korea in the men's team event, entered the final as the clear favorite through his world ranking of 49.

With the defending champion Paradorn Srichaphan from Thailand out of the tournament due to a wrist injury, Lee looked on course to pick up the gold. But another Thai, Danai Udomchoke, rose to the occasion.

Lee, who suffered a bad fever on Tuesday, did not have the stamina to match 104th-ranked Udomchoke before losing at 7-5, 6-3.

"The fever came after my match against Mamiit (in the semifinal on Tuesday). I even thought I might not be able to play today. I lost in the end, but I did my best," said Lee.

"I lost my strength from the fever."

China took the second gold in women's doubles as their doubles specialists Zheng Jie and Yan Zi outshone Chinese Taipei's Chan Yung Jan and Chuang Chia Jung 6-1, 7-6 (7-5).

It was also Zheng's second gold as she also took women's singles title by beating Sania Mirza from India on Wednesday.

"We trained very hard ahead of the Games so we were well-prepared. We are very happy to win the gold medal. We will try to keep the form and achieve good results next year," said Yan.