Mao Saigo came through a five-way play-off to win the Chevron Championship and claim the first major title of her career.
She carded a birdie at the 18th hole to record a final round 74 and secure a play-off spot along with American Lindy Duncan, Ariya Jutanugarn of Thailand, South Korea's Hyo-Joo Kim and China's Yin Ruoning.
All five finished on seven under par at The Club at Carlton Woods in Texas to set up the largest play-off at an LPGA major.
Jutanugarn, a two-time major champion, had led for most of the final day and needed a par at the last hole to win but, after her ball only moved slightly when she nearly missed it completely with her third shot, she carded a bogey.
At the first play-off hole - which was the par five 18th - Kim, Yin and Jutanugarn made par and there was a bogey for Duncan.
Saigo then sank a five foot putt to win it with a birdie to claim her first victory in the United States.
"I was so laser focused and nervous and really in the zone," said Saigo. "All I could think of was the ball in front of me. I couldn't see anything else.
"I was shaking from nervousness, but I did my best to calm down and I shot and it went in."
Speaking through a translator, she added: "It was my dream to earn this major.
"It is my first time to win this tournament. I was able to realise my dream and I'm very happy about this."
Asked about her aims for the future, Saigo said: "I still have four more majors to go, and I want to shoot for number one in the world. I will do my best in the remaining four majors."
Duncan, who was in the final group with Saigo and also trying to win a first major, birdied the 18th hole to make the play-off.
"I think I'll take so many great memories but also like an internal strength to just keep pushing no matter what, no matter how it feels," she said.