Rookie Patty Tavatanakit claimed her first major despite a stunning record-equalling round of 62 by Lydia Ko at the ANA Inspiration in California.
Thailand’s Tavatanakit, 21, shot a four-under 68 to complete a wire-to-wire victory at Rancho Mirage as she finished two clear of New Zealand’s Ko.
Ko set a tournament-record 29 on the front nine and matched Lorena Ochoa’s record low score for a round.
Tavatanakit is the first rookie to win the event since Juli Inkster in 1984.
“I just wanted to be done since this morning,” she said on Sunday, after claiming her first LPGA title.
“I didn’t get a lot of sleep last night, but I meditated twice this morning and just stayed patient. I knew I had to be really strong mentally.”
Ko, who won the tournament in 2016, made seven birdies and an eagle on the first 11 holes of the Dinah Shore course to threaten Tavatanakit’s lead.
However Ko – who became world number one aged 17 but who has been winless since April 2018 – made just one birdie in the final seven holes.
“It just shows it doesn’t matter how far back you are, you can always go for it,” added the two-time major winner, who had started the day eight shots adrift.
Ko’s bogey-free 62 was not enough to secure a ‘comeback’ title just hours after Jordan Spieth managed the feat in Texas, but it is the lowest final round in LPGA major history and suggests her rebuild with coach Sean Foley is close to bearing fruit.