Ted Potter Jr. came through a final-round tussle with Dustin Johnson to claim a three-stroke win at the AT&T Pebble Beach Pro-Am.
The 34-year-old threatened a sub-60 round during the third round and continued his impressive play on Sunday, posting a three-under 69 to secure a first PGA Tour victory since 2012.
Four birdies in a six-hole stretch on the front nine lifted Potter ahead of playing partner Johnson, who picked up a shot at the par-five last to close a level-par 72 and grab a share of second.
Johnson was joined on 14 under by Phil Mickelson, Chez Reavie and Jason Day, with Kevin Streelman a further stroke back following a four-under 68.
The world number 1 slipped further adrift when he failed to get up-and-down from a greenside bunker at the eighth and missed from six feet to save par at the 11th, as Potter reached the turn two ahead.
Defending champion Jordan Spieth ended the week in a share of 20th, with Jon Rahm a further shot back after an erratic final-round 76