China's reigning table tennis champion Wang Nan has been knocked out of the women's singles in the quarter-finals.
The world champion for the past three years and second seed lost 7-11 7-11 13-11 9-11 8-11 to Beijing-born Singaporean Li Jia Wei, the sixth seed.
But China's Zhang Yining beat Croatian Tamara Boros in four straight sets to book a semi-final meeting with South Korean third seed Kim Kyung Ah.
Li will play North Korea's Kim Hyang Mi in the other semi-final match.
China's top seeds Niu Jianfeng and Guo Yue were defeated 4-1 in the women's doubles semi-finals by their compatriots Wang Nan and Zhang Yining.
The two Chinese pairs were almost certain to meet in the final but a new rule stops teams from the same country being in the same half of the draw.
The victorious second seeds will now face South Korea's Lee Eun-sil and Seok Eun-mi for the title after the third seeds beat compatriots Kim Bok-rae and Kin Kyung-ah 4-0.
Danish duo Michael Maze and Finn Tugwell sprung a surprise in the men's doubles quarter-finals.
The unfancied pair beat Swedish veterans Jan-Ove Waldner and Jorgen Persson, who had knocked out China's second seeds, 4-1 in front of an excited crowd.
China's number one pairing Chen Qi and Ma Lin also brushed aside Poland's Lucjan Blaszczyk and Tomasz Krzeszewski 4-1.
In the other men's doubles semi-final, Russians Dimitrij Mazunov and Alexei Smirnov will play third seeds Ko Lai Chak and Li Ching from Hong Kong.
In the men's singles, top seed and world number one Wang Liqin will play Hong Kong's Ko Lai Chak in the quarter-finals on Friday.
Trying to join him in the semi-finals will be team-mate Wang Hao, who will play Taiwanese Chuan Chih-Yuan.
China has won all eight golds in the men's and women's singles and doubles events at the past two Olympics.