Pornpawee Chochuwong stunned world champion Pusarla V Sindhu to book her place in the women's singles quarter-finals of the US$1 million China Open in Changzhou on Thursday.
The 15th-ranked Thai fought back after dropping the first game to knock out world No.5 Sindhu from India 12-21, 21-13, 21-19 to join sixth seeded compatriot Ratchanok Intanon in the last eight of the BWF World Tour Super 1000 event.
Earlier, Ratchanok eased past home hope Chen Xiaoxin 21-14, 21-11 in their second round match.
Pornpawee will take on third seed Chen Yufei of China in Friday's quarter-finals, while Ratchanok will meet Japan's Sayaka Takahashi.
Chen avoided an upset at the hands of South Korean teenager An Se-Young, coming from behind to win their last 16 round encounter 20-22, 21-17, 21-15.
Busanan Ongbamrungphan, the other Thai player in the women's singles competition, was due to play Kim Ga-Eun of South Korea in a late match on Thursday night.
In her first tournament back after a knee injury sustained during the Indonesia Masters final in January, defending champion Carolina Marin of Spain defeated Zhang Beiwen of the United States 21-17, 21-12 to progress to the quarter-finals.
Marin will play China's He Bingjiao in the last eight after the seventh seed defeated Sung Ji-Hyun of South Korea in straight games 21-15, 21-11.
Also advancing were Thai mixed doubles stars Dechapol Puavaranukroh and Sapsiree Taerattanachai.
The fourth seeded duo survived a scare to defeat Mark Lamsfuss and Isabel Herttrich of Germany 19-21, 21-10, 21-11.
They will play Goh Soon Huat and Shevon Jemie Lai of Malaysia for a place in the last four.
Dechapol and Sapsiree were silver medallists at the world championships in Basel, Switzerland, last month.
Sapsiree was unable to complete a double. She and playing partner Puttita Supajirakul lost their women's doubles second round match against Kim So-Yeong and Kong Hee-Yong of South Korea 13-21, 13-21.