Yang Wei and Zhang Jiewen defeated defending champions Gao Ling and Huang Sui to win the women's doubles title at the World Badminton Championships.
The top seeds came through a tough final to beat their fellow Chinese and second seeds 17-16 15-7 in Anaheim.
In the men's singles semi-finals, China's top seed Lin Dan beat Denmark's Peter Gade 15-9 13-15 15-10.
Indonesia's Olympic champion Taufik Hidayat beat Malayasia's Lee Chong Wei 15-3 15-12 in the other semi-final.
China's Zhang Ning and Xie Xingfang, the top seeds, will contest the women's final.
Xingfang rallied to overcome unseeded teenager Cheng Shao-Chieh 2-11 11-5 11-6 while Ning saw off sixth seed Xu Huaiwen 11-7 11-9.
In the men's doubles semi-finals, American duo Tony Gunawan and Howard Bach, the 13th seeds, upset fourth seeds Luluk Hadiyanto and Alven Yulianto, of Indonesia, 15-9 15-13.
They are now assured of at least a silver which will be the first ever medal for the United States at a badminton world championship.
Second seeds Candra Wijaya and Sigit Budiarto, of Indonesia, booked their place in the doubles final by defeating Malaysia's Koo Kien Keat and Chan Chong Ming 15-9 15-11.
Meanwhile, China's Xie Zhongbo and Zhang Yawen defeated Daniel Shirley and Sara Runesten-Petersen of New Zealand 15-8 15-8 in the mixed doubles semi-finals.
Indonesian fourth seed Nova Widianto and Lilyana Natsir beat Thailand's Sudket Prapakamol and Saralee Thungthongka 15-3 15-12 in the other semi.