Kevin Kisner triumphed in the Dean & DeLuca Invitational at Colonial, despite a Sunday charge by defending champion Jordan Spieth.
Kisner made his move when he birdied the first three holes on the back nine to take the lead in the PGA Tour event in Texas, and his final round of 66 proved good enough for a one-shot victory.
The American finished at 10-under-par and clinched victory with a gutsy par save at the last after a wayward tee shot and an approach that finished off the back of the green.
He triumphed by one stroke, with Spieth (65), Sean O'Hair (66) and Jon Rahm (66) finishing in a tie for second, a shot ahead of third-round leader Webb Simpson (71).
Spieth shot a bogey-free round, and was standing on a chair to see over the crowd at the 18th green as Kisner putted up the mound to within five feet of the cup before then making the winning putt.
Moments before that, Rahm had a chance to reach 10-under himself, but he put a 10-foot birdie putt just left of the hole.
The 33-year-old Kisner is the World No 45 and was claiming his second PGA Tour victory in 148 starts since his debut in 2011.
He has been in great form in 2017 and had already been runner-up twice this year.
Kisner told Sky Sports: "I'm just honoured to be the champion here and to come back every year and see my name on that wall is going to be something special.
"I'm just happy to win any tournament but especially here, I love this place."
Paul Casey was in the mix after round three but he finished with a 73 to tie for 10th at four-under.