An appeal from South Korea over the expulsion of two pairs from the London 2012 women's doubles competition has been rejected.

The Badminton World Federation also announced that Indonesia withdrew an appeal against their disqualification.

The Chinese top seeds, the two pairs from South Korea and the one from Indonesia deliberately played to lose in an attempt to manipulate the quarter-final draw at Wembley Arena last night, it has been claimed.

All eight players have now been disqualified.

China's delegation said it 'fully respected' the decision to disqualify their pair Yu Yang Wang Xiaoli from the Olympics.

"The behaviour by Yu Yang and Wang Xiaoli on court violated the Olympics ideal and the spirit of fair competition. The Chinese delegation feels distressed over this matter," the delegation said in an emailed statement.

Eight women badminton players were disqualified from the Games on Wednesday for not trying to win their goup matches to secure a more favourable draw.

The decision knocked out China's world champion pair of Yu and Wang along with South Korean pairs Jung Kyung-eun and Kim Ha-na, and Ha Jung-eun and Kim Min-jung.

Indonesia's Greysia Polii and Meiliana Jauhari were also expelled for their involvement in the matches on Tuesday.

On the court, Japan's Sayaka Sato left the Wembley Arena in tears after being forced to pull out of her Olympic round-of-16 clash due to injury.

The 12th seed held a 15-11 advantage in the first game of her women's singles clash against Denmark's fifth seed Tine Baun but then badly twisted her ankle.

She tried to play on after receiving lengthy treatment but found it too difficult and was forced to accept her London 2012 bid was over with the score at 15-14.

The headlining men's singles showdown between the past two Olympic champions, Beijing winner Lin Dan and Athens gold medallist Taufik Hidayat, went the way of form.

Lin, the Chinese second seed and hot tournament favourite, was far too strong for the Indonesian and won 21-9 21-12 in 46 minutes.

Both players have said this is likely to be their final year of competition and Lin said: "This is probably the last time Taufik and I will play (each other) on these courts so I really cherish this match."

Russia's Valeria Sorokina and Nina Vislova beat South Africa's Michelle Edwards and Annari Viljoen 21-9 21-7 to book a semi-final against Chinese second seeds Tian Qing and Zhao Yunlei in the tainted women's doubles event.

Canadians Alex Bruce and Michele Li overcame Australia's Leanne Choo and Renuga Veeran 21-9 18-21 21-18 to set up a last-four clash with Mizuki Fujii and Reika Kakiiwa, the fourth seeds from Japan.