The Thai teenage sensation collected seven birdies and a brilliant eagle two on the par-4 13th to grab a one-stroke first-round lead over Korean amateur Minsol Kim.
American Andrea Lee and home hopes A Lim Kim and Yaeeun Hong share third at six under, with Steph Kyriacou the leading Australian six shots off the pace after an opening-round 69.
Minjee Lee, in a seemingly four-way battle for LPGA player-of-the-year honours, carded a two-under 70 to be in a tie for 19th. She is joined by fellow Australians Hannah Green and Su Oh.
Lee and Thitikul could usurp defending champion Jin Young Ko from the top ranking with a victory on Sunday, with the Thai in the box seat after a sizzling, bogey-free opening to the third-last event of the LPGA season.
Thitikul has already won twice in her maiden season on the LPGA Tour to be in with a chance of claiming both the rookie and the player of the year awards.
Three players carded 68s and were five off the lead: New Zealand's former world No.1 Lydia Ko and US pair Lilia Vu and Alison Lee.
Minsol Kim, in addition to getting off to a quick start with a 64, got to play with a personal hero. It is also her first year on the tour.
"When I was younger, I actually came as a gallery to watch the BMW Championships, and I remember thinking that Sung Hyun Park was really cool," Kim said.
"So today, to play side by side with her, it was a real honour."
Park, who has won two majors, had a 69.
- with Associated Press
29°C