China regained the lead as Li Junhui and Liu Yuchen downed Kim Astrup and Anders Skaarup Rasmussen 21-18, 21-16 in men's doubles before Chen Yufei cruised over Mia Blichfeldt 21-16, 21-17 in women's singles to seal the victory.

"I had a better performance than the previous days, and hope to tune up for the coming matches," said Chen.

Without injured 6th-ranked Son Wan-ho and 10th-ranked Sung Ji-hyun, South Korea felt helpless in this do-or-die battle against Thailand.

Thailand built a 2-0 lead after winning the mixed doubles and men's singles before Kang Min-hyuk and Kim Won-hoIn pulled one back by overturning Tinn Isriyanet and Kittinupong Kedren 19-21, 21-17 and 21-14.

The reigning champion put all its hope in the 17-year-old An Se-Young, who stunned world No 1 Tai Tzu-ying to inspire South Korea edge Chinese Taipei 3-2 on Wednesday.

But the rising star was upset by Ratchanok Intanon, the former World Championship winner, 21-15, 21-17 in the women's singles, sawing Thailand reached the semifinals for the third time.

"It's a great pity to lose the match. I took most time to defend and seldom got the chance to attack as Intanon is quite aggressive. Overall I learned a lot during Sudirman Cup," said An who couldn't help but burst into tears after the loss.

Other two quarter-finals will see Chinese Taipei battle with Indonesia and Malaysia take on Japan on Friday.