Wild card holder Trinh Linh Giang lost 2-6, 6-7 (2) to No 7 seed Pruchya Isaro of Japan in the quarter-finals of the men’s singles event.
He was the last Vietnamese player on court, the others were ousted from the early rounds.
Isaro will play No 5 Yu Cheng-yu of Chinese Taipei in the semi-finals today. Yu won yesterday 6-4, 6-2 over No 4 Alexios Halebian of the US.
The other semis will see a clash between Son Ji-hoon and Nam Ji-sung in an all-South Korean match.
The doubles semi-finals are also organised today.
Nam and Song Min-Kyu of the Republic of Korea will meet No 4 duo Halebian and Gengo Kikuchi (Japan) in the first match, and Thailand’s Chanta Thanapet and Rakuangchon Voracho will face their fellows Kerdlaphee Kittirat and Kovapitukted Palaphoom.