American Lilia Vu snatched the LPGA Thailand trophy from Thai rookie Natthakritta Vongtaveelap, scoring a one-shot victory after a helter-skelter final round on Sunday.
The Californian had realistically only been in contention for a top-five finish as players teed off in gusty headwinds at the Siam Country Club in Pattaya but carded an eight-under-par final round of 64 to win.
Natthakritta, 20, had also hit a 64 in Saturday's third round to maintain the tournament lead but the title slipped from her grasp with a one-under closing round of 71.
Vu's fortunes changed at the eighth hole, where she hit the first of five consecutive birdies.
That set up the 25-year-old for a winning 22-under-par total of 266, her first Rolex LPGA tour victory that came with prize money of $255 000.
"Yesterday I was thinking – my dad was telling me one good round tomorrow and I could win. That's all I kept thinking about," she said.
Vu almost stumbled at the tricky 17th hole before righting herself to save par and maintain her narrow lead.
"Today I basically just blacked out and tried to birdie every single hole," she said.
"I always want to win when I'm out here," she said. "I just wanted to allow it to happen and it finally did."
It was a bitter end to a stellar performance for Natthakritta, who came out of relative obscurity after receiving a tournament invitation from a sponsor.
She had grabbed a shock lead by the halfway point of the tournament with successive rounds of 65 and 64 in front of enthusiastic local supporters.
Natthakritta started six shots clear of Vu, and two ahead of her nearest rival, compatriot Atthaya Thitikul, but intense nerves betrayed her on a scorecard that included four bogeys and a double bogey.
There was a glimmer of hope for Natthakritta with a steadying par at the 13th, followed by an eye-catching birdie at the par-three 14th.
However, it was too late to stop Vu's steady progress through the back nine after her earlier birdie blitz.
Atthaya, a former world No 1 and runner-up in the 2021 tournament, finished third after a final-round 68.
Top-ranked Lydia Ko played solid if unexciting golf to move quietly up the scoreboard.
But the New Zealander was undone by a double-bogey and bogey finish on the final two holes to card a 69 for a share of sixth.