South Korea's Yoo Sun-young sunk a 15-foot put in the first hole in the sudden death play-off to lift the Kraft Nabisco Championship in California.
Yoo, 25, won her first Major title after compatriot Kim In-kyung missed a one-foot putt to win in regulation.
"I am speechless, I played pretty solid today," Yoo, who matched Kim's final round of three-under-par 69, said. "I was hoping today for some luck."
Catriona Matthew's four-under made her the top-placed Brit in tied 15th place.
England's Jodi Ewart finished three shots further back in joint 26th place while 16-year-old Charley Hull, from Kettering, ended her first professional tournament in tied 38th place on one-over.