American Andrew Landry was reeling after blowing a six-stroke lead on the back nine on Sunday afternoon at The American Express tournament in California.
But the Texan regained control and held his nerve to break a tie with Mexico's Abraham Ancer by holing a two-metre birdie putt on the 17th hole.
Landry then made another crucial putt on the 18th for a five-under 67 and a two-stroke victory overall with a 26-under 262, erasing memories of his loss in a playoff at the tournament two years ago.
"This is a golf course that has suited me very well in the past," Landry said.
"And just to look back on some of the things that happened a couple years ago and then now, just to be able to finally get it done.
"I didn't want to have to go back into a playoff again."
Ancer, trying to become the third Mexican winner in PGA Tour history and first since 1978, matched the Stadium Course record with a 63.
"All week, really, I hit the ball great off the tee and iron shots, and in the first three rounds, I feel like I didn't score as low as I should have for how good I hit the ball," Ancer said.
Landry appeared to be cruising to victory when he birdied the first three holes on the back nine to open the six-shot lead.
But he bogeyed the next three holes, made a par on the par-5 16th that felt like another bogey, and was tied when Ancer birdied the 17th.
He opened with a 66 on the Stadium Course, shot 64 in the second round at La Quinta Country Club and had a 65 on Saturday on PGA West's Jack Nicklaus Tournament Course.
Sydneysider Cameron Davies continued his good form and tied for 29th place, with a 14-under 274,
- Steve Larkin, Australian Associated Press