Paula Creamer knocked in a long birdie at No.15 to retake the lead and held on en route to a one-stroke victory at the Samsung World Championship on Sunday.
It was the fourth victory of the year and eighth career for the 22-year-old Californian, who finished with a three-under-par 69.
The four wins this season are the most by an American player since Juli Inkster collected five in 1999.
Beyond adding to a strong campaign, it was an emotional win for Creamer, who broke into tears during a TV interview when she realised that she claimed the tournament near her hometown of Mountain View.
"This means a lot. That is (a) big win for myself," she said later. "I put so much pressure on myself every time I come here and to finally have one, it feels really good. I'm very excited."
"I briefly looked at my phone and people kept saying, 'Did I see you cry? I didn't think you had emotions and all of this.' It does. It really means a lot to me, this win."
Creamer came into the final round with a one-shot lead following a 68 on Saturday. That slim edge disappeared on the back nine Sunday when Korean Kim Song-hee birdied the 14th to pull even at eight-under.
As if losing the lead was not enough, two-time defending champion and world No.1 Lorena Ochoa and the Hall of Famer Inkster both notched a birdie on No.16 to pull within a stroke. Also moving to seven-under was Suzann Pettersen with a birdie at the 15th.
Despite the crowd at the top of the leaderboard, Creamer did not lose her focus, coming up with a birdie putt from 25 feet out on her next hole to move back ahead. She maintained that lead until the 18th, when a shaky birdie attempt nearly cost her.
However, Creamer was able to lip in a par putt to seal the win, ending up at nine-under 279.
"Honestly, I didn't see it go in," Creamer said about the clinching putt. "All I heard was the people cheer for it, then I was like, it was like the longest two seconds of my life having it roll into the hole."
Seeking her first win on the LPGA Tour, Kim finished a shot behind following a final-round 68.
It was the second time the 20-year-old was a runner-up this season, ending up 11 strokes behind Ochoa at the Corona Championship in April.
"Going in (Saturday), I didn't have a great feel for my shots, so I was a little worried coming into the round today," Kim said through an interpreter. "But I played pretty well. I had a lot of opportunities but I wasn't able to convert all of them, so I'm a little frustrated."
Ochoa, who was trying to become the fourth player to win this event at least three times, ended up in a tie for third at 281 following a 69.
The Mexican finished tied with Inkster (68), Pettersen (68) and Angela Stanford (70).
Australian Katherine Hull was a stroke further back in outright seventh, while compatriot Karrie Webb struggled to a five-over-par total.
Ochoa had a much better showing on the back nine than she had on Saturday, notching an eagle at the par-five 10th and the birdie on 17th. However, she went into a bunker on her approach of the 18th green before having