Patrick Cantlay holed a 17-foot putt to beat Bryson DeChambeau and win the BMW Championship in a six-hole sudden-death play-off at Caves Valley Golf Club in Baltimore.
Cantlay secured his play-off spot with a 21-foot putt for birdie on the 18th.
The title is the 29-year-old American’s third on the PGA Tour this year and he enters next week’s Tour Championship in first place in the FedEx Cup.
Rory McIlroy, who shot a 67, was five shots back in fourth.
Cantlay, the new world number four, also secured one of the six automatic places on the US Ryder Cup team.
He joins Dustin Johnson, Collin Morikawa, Brooks Koepka, Justin Thomas and DeChambeau in Steve Stricker’s team for the 43rd Ryder Cup at Whistling Straits next month.
A thrilling final-round battle between Cantlay and DeChambeau produced a feast of birdies as both shot 66s to finish on 27-under-par.
DeChambeau, who narrowly missed out on a round of 59 two days earlier, missed four putts to win the tournament.
After a ding-dong shootout separated the two players from the chasing pack, DeChambeau led by one with one hole remaining.
However, Cantlay – who putted beautifully all week – holed from 21 feet and DeChambeau’s birdie effort slid past to send the two players into extra time.
With DeChambeau in for par at the first extra hole, Cantlay nearly holed out for a birdie from the greenside rough, and then sunk his return putt to extend the play-off, with DeChambeau failing with putts to win on the second and third extra holes.
On the fourth, DeChambeau managed a courageous par despite finding water with his drive to force a fifth, which both players birdied.
Returning to the 18th hole again, both players reached the green in two and Cantlay’s 17-foot putt for birdie proved enough to secure victory when DeChambeau missed his own eight-foot attempt.
“I’m as focused as I can be on every single shot, and I try not to let my mind get past the moment that I’m in,” Cantlay said, following the win.
“Then I kind of let the chips fall where they do. I try not to get caught up in being out-driven 45 yards or whatever it is. I just try and lock in and do my absolute best in that moment, and my best is pretty good.”