Ted Potter Jr claimed his first PGA Tour title for six years with a convincing three-shot win at the AT&T Pebble Beach Pro-Am, as Shane Lowry ended slipped right down the leaderboard after closing with a patchy two-over-par 74.
Potter, 34, was tied for the lead with world number one Dustin Johnson heading into the final round in California but while the latter could only muster a level-par 72, Potter followed his stunning 62 on Saturday with a three-under 69.
His 17-under-par total was three clear of Australia's Jason Day and Americans Johnson, Chez Reavie and Phil Mickelson, with the latter producing a fast finish for the second Sunday in a row with three birdies in his last five holes.
Lowry was the only Irishman to make the cut after a superb four-under-par 68 but three bogeys left him five-under for the tournament in a tie for 43rd.
Potter made a nervous start with a three-putt bogey from inside 20 feet on the opening hole, but birdied the long next and surged ahead as fine approaches to the fourth and sixth set up close-range gains.
A chip-in birdie on the seventh completed Potter's scoring and he parred his way in for a first triumph since landing the 2012 Greenbrier Classic.
He told the PGA Tour website: "It's just so good right now, to get my second career win after five years away from it. Going back to the masters, it will definitely be another dream come true.
"Try to get back there and win the Par 3 Contest again - that was a lot of fun.
"This has just been a blast this week and it's unbelievable right now."
Mickelson's closing flourish saw him sign for a round of 67, with Reavie carding a 68 and Day 70.
"This has been a really fun week," Mickelson told Sky Sports Golf.
"I gave it a shot on the back nine - it was a good solid round.
"It was nice to feel the nerves and make a couple of birdies down the stretch. I'm hitting it as well as I have done in a long time."