Lin Dan of China is through to the Olympic badminton men's singles semi-finals after a closely fought win over Sho Sasaki.
The reigning Olympic and world champion held off a fightback from his Japanese opponent to win 21-12 16-21 21-16.
He will face Hyun Il Lee on Friday after the South Korean beat Chen Jin of China 21-15 21-16.
Top seed Lee Chong Wei of Malaysia also reached the semi-finals, where he will play China's Chen Long.
Lee, runner-up to Lin in 2008, comfortably beat India's Kashyap Parupalli 21-19 21-11, while Chen held off Denmark's Peter Gade, the former world number one, 21-16 21-13.
Three Chinese women will feature in the last four of the women's singles along with Saina Nehwal of India.
Fourth seed Nehwal came through in controversial circumstances against Europe's top player, Denmark's Tine Baun.
Baun started to celebrate as she left a Nehwal shot to drop out, levelling the match at 1-1, but to her astonishment it was called in.
She protested to no avail and then dropped the next five points to lose 21-15 22-20.
Top seed Wang Yihan brushed off Shao Chieh Cheng of Chinese Taipei 21-14 21-11, Wang Xin avoided an upset to beat Thailand's Inthanon Ratchanok 17-21 21-18 21-14 and Li Xuerui overcame Hong Kong's Yip Pui Yin 21-12 22-20.
China are guaranteed at least one gold as mixed doubles top seeds and world champions Zhang Nan and Zhao Yunlei setup a final with number two pair Xu Chen and Ma Jin.
Both came through three-game battles against Denmark's Joachim Fischer and Christinna Pedersen and Indonesia's Tontowi Ahmad and Liliyana Natsir respectively. For the first time in Olympic history, Indonesia will not win a badminton gold medal.
Meanwhile, two of the women's doubles pairs reprieved by this week's match-fixing scandal will play-off for the bronze medal.
Russia's Valeria Sorokina and Nina Vislova will face Canadians Alex Bruce and Michelle Li after defeats in their respective semi-finals to the Tian Qing/Zhao Yunlei and Mizuki Fujii/Reika Kakiiwa partnerships.
Bruce and Li put up the strongest fight, going down 21-13 to the Japanese in the third game.
The men's doubles competition is still at the quarter-final stage.
Top seeds Cai Yun and Fu Haifeng won their all-Chinese clash with Chai Biao and Guo Zhendong to setup a meeting with Malaysia's Koo Kien Keat and Tan Boon Heong.
The other semi-final will be between Korean second seeds Chung Jae-sung and Lee Yong-dae and Denmark's third seeds Mathias Boe and Carsten Mogensen.