Japan's Miyuki Maeda and Satoko Suetsuna upset defending Olympic champions Yang Wei and Zhang Jiewen

Lee Chong Wei, Malaysia's top bet for a medal in the Olympics, stamped his class over Ronald Susilo of Singapore 21-13, 21-14 in his opening second-round match today as all badminton seeds took to the courts.

Japanese badminton pair Satoko Suetsuna and Miyuki Maeda advanced to the women's doubles semifinals at the Beijing Olympic Games after an 8-21, 23-21, 21-14 win over top seeds Yang Wei and Zhang Jiewen of China on Monday.

Suetsuna and Maeda came back from one game down and a 19-16 deficit in the second game to pull off a major upset victory over the world No.1 pair and defending Olympic champions in their quarterfinal matchup.

"I can't believe this," Suetsuna said. "I just didn't want to play in a way I might regret, so I kept on attacking to the limit of my strength. Now that we've come this far, we'll definitely go for a medal."

Suetsuna and Maeda, ranked eighth in the world, became the first Japanese to make the semifinals of any badminton event since the sport became an official Olympic sport at the 1992 Barcelona Games.

Compatriots Kumiko Ogura and Reiko Shiota face second seeds Du Jing and Yu Yang of China in another quarterfinal match later Monday.

In the women's singles, Japan's Eriko Hirose was knocked out after a 21-12, 16-21, 21-6 loss to No. 5 seed Hongyan Pi of France in the third round.