Seventeen-year-old Lydia Ko broke free from a late tie with So Yeon Ryu, hitting a wedge to within four feet fto set up a birdie on the 72nd hole on Sunday to win the Marathon Classic in Sylvania, Ohio.
She became the youngest player to top $1 million in career earnings on the LPGA Tour.
"I'll probably see that going into my mom's account," she said with a laugh, referring to the $210,000 she got for winning Sunday's Marathon Classic.
Ryu had poured in a big-breaking, 25-foot birdie putt on the 17th to pull even.
But then Ko stuck her approach at the par-5 closing hole and calmly rolled in the birdie putt for a six-under-par 65 that left her at 15-under 269. It was her second LPGA win as a pro to go with the two Canadian Open titles she grabbed as an amateur.
Ryu pushed a six-footer wide of the cup at the 18th that would have forced a playoff.
Ko was resilient, also shrugging aside a challenge from veteran Cristie Kerr, who pulled into a tie with her on the homeward nine.
Ko is roughly 17 months younger than Lexi Thompson, who previously was the youngest to hit the $1 million mark in LPGA earnings. She has shown incredible consistency in her rookie year on tour, making the cut in all 15 tournaments she's entered. She has six top-10 finishes in addition to her wins, with five of those being top-fives.
The 5-foot-5 Ko, who started the final round in fifth place, give shots behind co-leaders Laura Diaz and Lee-Anne Pace, was behind the 18th green trying to watch what happened over a large mass of spectators and Ryu lined up her final putt.
"I couldn't see it properly. I was behind some people," she said after her second LPGA Tour victory that matched the two Canadian Open titles she won as an amateur. "But I kind of could tell what happened by the crowd's reaction."
Ryu finished with a 67 that left her at 270, and Kerr was next at 272. Kelly Tan (67), Katherine Kirk (68) and Pace (71) were at 273.
Pernilla Lindberg matched Ko for the day's low round with a 65 and she led the group at 274, which also included last week's Women's British Open champion, Mo Martin, who had a 69.
Diaz, who led almost from the start after birdieing her first five holes on Thursday, lapsed to a 75 and finished at 277.
The start of the final round was delayed an hour by heavy fog.
Mark Rypien wins American Century Celebrity Golf Championship
Mark Rypien beat out Jeremy Roenick and Annika Sorenstam to win the weather-delayed American Century Celebrity Golf Championship on Sunday.
Rypien took the title for the first time since winning the inaugural event in 1990.
Lightning storms delayed play for more than three hours.
Rypien ran away from Roenick and Sorenstam, putting up big Stableford points on his back nine, going 5 under for a record-breaking third-round total of 33 points and 76 throughout the three-day event at Edgewood Tahoe Golf Course.
After finishing in second place in the past two years, Rypien broke through with a win in the 25th anniversary of the tournament.
Rypien won $125,000 from the $600,000 purse. Sorenstam and Roenick will each get $57,500 for tying for second in the event.