Top seed Saina played long rallies and used her effective smashes to stave off the challenge from the hosts eighth seed Taerattanachai 21-10 22-20 in the women's singles competition.
The world number five, who is one of the medal prospects for India at the London Olympics, will next take on the winner of the match between Japan's Nozomi Okuhara and third seed Porntip Buranaprasertsuk of Thailand tomorrow.
Saina produced a dominant show in the first game as she reeled off eight straight game to open up a 8-0 lead. The Indian didn't give any chance to her rival and held her fort to lead the match 1-0.
In the second game, Saina had opened a narrow 4-2 lead but Taerattanachai registered six straight points to grab the lead. Saina then slowly and steadily narrowed the gap and caught up with the Thai at 19-19 before sealing the issue in her favour at the CU Sport Complex.
Saina had defended her title at the Swiss Open Grand Prix Gold in March in Basel, Switzerland early this year.