
Pitchamon Opatniputh stunned Ratchanok Intanon in the second round of the US$240,000 (8,160,000 baht) Princess Sirivannavari Thailand Masters 2025 at Nimibutr Stadium on Thursday.
The world No.119 rallied from a game down to upset the second seed and world No.10 17-21, 21-18, 21-16 to reach the women's quarter-finals of the World Tour Super 300 event.
Pitchamon will meet eighth seed Komang Ayu Cahya Dewi of Indonesia in the last eight on Friday.
Earlier, top seed Pornpawee Chochuwong moved safely through to the quarters with a 21-15, 21-11 win over Chen Su-yu of Taiwan. She will face Sim Yu-Jin next after the Korean knocked out Tidapron Kleebyeesun 21-15, 21-12.
In other women's singles matches, Thamonwan Nithiittikrai eliminated fourth seed Line Hojmark Kjaersfeldt of Denmark 22-20, 21-13 while seventh seed Pornpicha Choeikeewong scraped past Thai compatriot Lalinrat Chaiwan 25-27, 22-20, 21-19.
Meanwhile, the mixed doubles pair Dechapol Puavaranukroh and Supissara Paewsampran reached the quarter-finals with an easy 21-9, 21-4 victory over Yeung Shing Choi and Lui Lok Lok of Hong Kong.
The fourth seeds will play seventh seeds Adnan Maulana and Indah Cahya Sari Jamil of Indonesia in the quarter-finals.
Dechapol and Supissara are chasing their second title of the year after winning the season-opening Malaysia Open earlier this month.
Dechapol's former mixed doubles partner Sapsiree Taerattanachai and Supak Jomkoh bowed out after losing to third seeds Pakkapon Teeraratsakul and Phataimas Muenwong 21-15, 18-21, 18-21.
Dechapol and Sapsiree won the mixed doubles title last year.
Another mixed pair, Ratchapol Makkasasithorn and Nattamon Laisuan, also progressed to the last eight but Surasit Ariyabaraneekul and Atitaya Povanon crashed out.
Men's singles player Kantaphon Wangcharoen exited the tournament after losing to Zhu Xuanchen of China 15-21, 21-13, 14-21.
Two-time defending champions Benyapa Aimsaard and Nuntakarn Aimsaard were set to face Leung Yuet Yee and Ng Wing Yung of Hong Kong in the last 16 of the women's doubles event later last night.