Adam Long sunk a 14-foot birdie putt at No. 18 to clip Phil Mickelson and Canada's Adam Hadwin on the final hole Sunday at the Desert Classic in La Quinta, Calif., claiming his first title in his sixth career start on the PGA Tour.

The trio came to the 18th hole on the Stadium Course -- the site for Sunday's action after three courses were used on Thursday, Friday and Saturday -- tied at 25 under. Hadwin's approach found the back left bunker, while Mickelson, from the right rough, put his approach to 38 feet. Approaching from the left rough and about 35 yards closer than Mickelson, Long dropped his shot to 14 feet.

After Mickelson missed, Long buried a slight right-to-left breaker in the center of the cup, capping a bogey-free round of 7-under-par 65, Long's lowest career round on the PGA Tour.

"Honestly, I got a pretty good read off Phil's putt," Long said afterward. "It was one of those putts that you just stand over it and you just know you're gonna make it. You can't control that, but when you have that feeling, it's a good one, and I'm in disbelief right now."

The 31-year-old Long turned pro in 2010 but made just one PGA Tour start -- a missed cut at the 2011 U.S. Open -- before October. He tied for 63rd at the Safeway Open in October and was cut in all three events since before this week. Ranked 417th in the world entering the tournament, Long is projected to jump to No. 205 and to No. 12 in the FedEx Cup Standings. He also will take home winnings of $1.063 million after earning $13,568 the rest of the season to date.

Long had to be resourceful to chase down Hadwin, who used a 5-under 31 on the front nine to get to 25 under and take a two-stroke lead over Mickelson, who was 1 under on the front. Three strokes off the pace entering the back nine, Long chipped in from 16 feet for birdie at the 12th and then again from 20 feet at No. 15, which came just after he sunk a short putt for birdie at the 14th.

"The chip-ins were huge, and some putts on the front nine as well to just hang in there," Long said. "It was a huge thrill to play with Phil obviously. I've looked up to him my whole life, and I'm a big fan of his and he couldn't have been greater to me."

Mickelson began the day with a two-shot lead, but he opened and closed his front nine with bogeys, including a three-putt at No. 1. With two precise approaches, he made short birdie putts at Nos. 15 and 16 to regain a share of the lead, before a par-par finish left him a stroke short.

"I had a terrible putting day, I mean, one of the worst I can recall in a while," said Mickelson, who matched his career-low score with a 12-under 60 at La Quinta Country Club in the opening round. ."..I missed a bunch of short ones on the front and some birdie opportunities. It felt awful with the putter. I hit a lot of good shots today, though. I just couldn't get the ball to go in the hole."

Hadwin went cold after the turn, following a birdie at No. 11 with a bogey at No. 13 before five pars to finish. He missed birdie opportunities from five feet on No. 12 and just under 10 feet on No. 15.

Talor Gooch, the only player to go lower than Long on Sunday, fired an 8-under 64 to claim fourth place alone at 24 under for the tournament.

Dominic Bozzelli (66) finished two strokes back in fifth, with defending champion Jon Rahm (67) at 21 under for sixth place.