Sea Games gold medallist Suthasini Sawettabut came from behind to beat Han Xing of Congo 4-3 (11-9, 10-12, 7-11, 8-11, 11-6, 11-7 11-9).
Veteran Nanthana Komwong, who is competing in her fifth consecutive Olympics, beat Dina Meshref of Egypt 4-0 games (12-0 11-5 11-8 11-7).
In the men’s singles, Padasak Tanviriyavechakul beat Indian Soumyaji Ghosh 4-1 (11-8, 11-6, 12-14, 11-6 13-11).