Local star Ratchanok Intanon crashed out of the Yonex Thailand Open in the quarter-finals, losing 22-20, 21-12 to South Korea's An Se-Young on Friday.
Thailand now pin their hopes on mixed doubles pair Dechapol Puavaranukroh and Sapsiree Taerattanachai and women's doubles duo Jongkolphan Kititharakul and Rawinda Prajongjai who are the only local players in today's semi-finals.
In the women's singles, seventh seed An needed only 44 minutes to eliminate fourth-seeded Ratchanok in the US$1 million tournament at Bangkok's Muang Thong Thani.
"Today I had a chance to play with Ratchanok again. I made a lot of mistakes last time, but this time I reduced mistakes," An said.
"I got my timing right and my smash shots were quite accurate. As a result, I was able to win."
Ratchanok said: "I think in the beginning, I played too leisurely. I've played An before, but never like this. She came with more speed today. You can see how she had prepared for this match, every shot was incredible and she won on her own game."
An will be up against Carolina Marin of Spain in the last four after the Olympic champion defeated Thailand's Supanida Katethong 21-16, 21-16.
Top-ranked Tai Tzu-ying of Taiwan cruised past Canada's Michelle Li 21-11, 21-13.
The All England champion will next play Mia Blichfeldt of Denmark who beat Thai star Busanan Ongbamrungphan 21-13, 21-18.
In the mixed doubles, top seeds Dechapol and Sapsiree saw off Malaysia's Chan Peng Soon and Goh Liu Ying 21-18, 21-17.
"There was a bit of pressure as every point mattered but in the end we did not play their game and that gave us an advantage," Sapsiree said.
They will next face South Korean fourth seeds Seo Seung-Jae and Chae Yu-Jung who beat Hong Kong's Chang Tak Ching and Ng Wing Yung 21-16, 15-21, 21-4.
In the other semi-final, second-seeded Praveen Jordan and Melati Daeva Oktavianti of Indonesia will take on France's Thom Gicquel and Delphine Delure.
In the women's doubles, Jongkolphan and Rawinda beat compatriots Laksika Kanlaha and Atitaya Povanon 21-10, 21-17.
"I think we played okay today -- not too good and not too bad. In the second game, we had to put more pressure on our opponents, so as to not make it easy for them," Jongkolphan said.
In the semi-finals, the seventh-seeded Thais will meet fourth seeds Kim So-Yeong and Kong Hee-Yong of South Korea who defeated Chloe Birch and Lauren Smith of England 21-8, 21-11.
In the men's singles, world No.2 Chou Tien Chen of Taiwan defeated Malaysia's Lee Zii Jia 21-17, 21-15.
In the last four, he will be up against seventh seed Ng Ka Long Angus from Hong Kong who beat compatriot Leed Cheuk Yiu 21-17, 21-12.
Fourth seed Viktor Axelsen of Denmark had a light workout in his 21-14, 21-5 win against Jonatan Christie of Indonesia.
The Dane will next meet fifth seed Anthony Sinisuka Ginting, another Indonesian, for a place in tomorrow's final.
The Yonex Thailand Open is one of the three consecutive tournaments in the Asian leg in Bangkok.
It will be followed by the Toyota Thailand Open from Jan 19-24 and the HSBC BWF World Tour Finals 2020 from Jan 27-31.
South Korea's An Se-Young reacts during her match against Ratchanok Intanon.