Athens Olympic gold medallist Taufik Hidayat's last attempt at winning the Japan Open ended in defeat on Friday, while women's top seed Tine Baun was another surprise quarter-final casualty.
The 31-year-old Hidayat, who has announced he will retire next year, bowed out to his Indonesian team-mate Simon Santoso 9-21, 14-21 in Tokyo. He has never won the Japan Open, despite Olympic, world and Asian glory.
Baun meanwhile, who captured her first major title five years ago in the Japanese capital, crashed to a shock 21-17, 12-21, 18-21 defeat to sixth seed Porntip Buranaprasertsuk of Thailand.
There was no such trouble for the men's top seed, Lee Chong Wei of Malaysia, who defeated compatriot Chong Wei Feng 21-15, 21-15 in only 29 minutes to move closer to the title he won in 2007 and 2010.
"I played many practice matches against him and we know each other very well. I've never lost to him in either international or domestic tournaments," said Lee, 29.
Lee had to be satisfied with the silver medal to China's Lin Dan at the London Olympics, but his nemesis is not in Tokyo, along with the whole China team, after they boycotted the tournament over diplomatic tensions.
Lee plays Santoso in the semis on Saturday. The other semi-final match will be between Hu Yun of Hong Kong and Boonsak Ponsana of Thailand.
Hu, who defeated two-time champion Peter Gade on Wednesday and was the losing finallist in China last week, battled to a 24-22, 21-15 victory over eighth seed Nguyen Tien Minh of Vietnam to continue his excellent run of form.
Boonsak, who also eliminated 2008 champion Sony Dwi Kuncoro of Indonesia, thrashed Kazumasa Sakai of Japan 21-9, 21-6.
"I don't feel any fears against his (Nguyen's) shots because they are the shots I can comfortably hit back. I always feel confident whenever I play against him," Hu said.
"I'm happy about the win, not because my opponents were seeded. When I beat a stronger player, of course, I'm happier. I don't feel any pressure. I relax when I play and that's why I'm doing very well recently."
Another upset in the women's draw saw Eriko Hirose of Japan beat the fourth seed Bae Yeon-Ju of South Korea 21-7, 21-15 for a place against Porntip on Saturday.
Second seed Sung Ji-Hyun of South Korea safely went through, beating eighth seed Ai Goto of Japan 12-21, 21-16, 21-14. She faces Tai Tzu-ying of Taiwan, the winner over Ratchanok Intanon of Thailand 21-16, 21-16.
