World badminton mixed doubles champions Ra Kyung-min and Kim Dong-moon of South Korea reached the semifinals of the Singapore Open with a 15-8, 15-8 win over top seeds Zhang Jun and Gao Ling of China yesterday.

In another mixed doubles quarterfinal match, China's Zheng Bo and Zhang Jiewen beat Kim Yong-hyun and Lee Hyo-jung of South Korea 15-9, 15-3 at the Singapore Indoor Stadium.

In both the men's and women's singles quarterfinals, China grabbed four of the eight spots on offer in the US$170,000 tournament. China will have at least one player in men's singles semifinals as Bao Chunlai was playing Lin Dan.

China's Zhou Mi, the fifth seed, caused a minor upset in the women's singles with a 6-11, 11-9, 13-10 win over third-seeded Mia Audina of Holland.

She was joined in the last four by yet another player from China, world champion Zhang Ning, who beat compatriot Xie Xingfang 11-4, 11-3.

Meanwhile, the third semifinal slot in the mixed doubles was filled by Thais Sudket Prapamakol and Saralee Thungthongkam who beat England's Anthony Clark and Scot-land's Kirsten McEwan 15-4, 15-8.

In men's singles games, Singapore's Ronald Susilo was playing top seed and defending champion Chen Hong while former All-England champion Peter Gade of Denmark was meeting South Korea's Lee Hyun-il.

Earlier Susilo, the sixth seed, beat Korean Shon Seung-mo 15-6, 11-15, 15-5 on Thursday. The Indonesian-born Susilo has yet to beat Chen in their five previous meetings.

"Everyone has a chance to win and though I've played Susilo five times, every match is different," said Chen late on Thursday. "I don't think there have been much changes to his play, but I'm sure he has matured through all the competitions."

Gade had earlier defeated compatriot Peter Rasmussen 15-6, 15-6 in the third round. The earlier withdrawal of China's world champion Xia Xuanze leaves the bottom half of the draw wide open and gives Gade his best chance for a title since the 2002 US Open.