Tom Hoge birdies four of his final eight holes to win the AT&T Pebble Beach Pro-AM, edging out Jordan Spieth in the process.
Sunday's final round saw several players hold the lead at various stages, but Hoge's late surge came at a time when his more illustrious compatriot started to fade.
A three-shot swing occurred on holes 16 and 17, Hoge making two birdies in comparison to Spieth's bogey at the latter, and a par on the last secured a two-shot victory.
Hoge now has three top fours in his last five starts, a run of form which will see him move into the top 50 of the world rankings on Monday.
Spieth finished in second place on his own after Beau Hossler bogeyed the 18th hole, while Troy Merritt and Patrick Cantlay shared fourth spot.
Englishman Matt Fitzpatrick earned a share of sixth position after a final-round 68, with Ireland's Seamus Power securing another top-10 finish in ninth.