Jason Kokrak had played in 233 PGA Tour events before getting his first victory. The big hitter didn't have to wait nearly as long to win again, overcoming a local favourite to do it at Colonial Country Club.
Kokrak shot an even-par 70 in a final-group showdown on Sunday with Jordan Spieth to finish two shots clear at 14-under 266.
Overnight leader Spieth hit his approach shot to No.18 over the green and into the water to end his hopes of another home win in Texas.
While even on the day, Kokrak had five bogeys to go with five birdies. He twice needed two shots to get out of bunkers, and had back-to-back bogeys at Nos. 15 and 16.
But when he struck his final 4-foot putt, he followed the ball to the cup and finally broke into a smile.
A huge crowd followed the only contending group all day, most of them waiting to erupt for Dallas-native Spieth, who started the round with a one-stroke lead before a bogey-filled 73.
Instead of his second win at Colonial, he finished as the runner-up at Hogan's Alley for the third time.
It was still Spieth's eighth top-10 finish in his past 11 starts this year, one more top 10 than he had the previous two seasons combined.
"They were definitely rooting for the guy next to me," said Kokrak, who tied for third at Colonial last June.
"Both of us didn't have our A-game today. We grinded it out."
Kokrak, playing in his 16th tournament since winning he CJ Cup at Shadow Creek in October, became the third player with two PGA Tour wins this season - joining Bryson DeChambeau and Stewart Cink.
Four players tied for third on 10 under, Charley Hoffman signing for a 65 to move up 14 places on Sunday to finish alongside Patton Kizzire (67), Sebastian Munoz and Ian Poulter (both 68).
Sergio Garcia was in third place with the final round began, four strokes behind Kokrak and five behind Garcia, but the 41-year-old Spaniard, who got the first of his 11 PGA Tour wins 20 years ago at Colonial, started with a wayward tee shot and bogeyed the opening par 5, then had had a three-putt for double bogey at No.3.
He shot a 76 and tied for 20th.
Australian Cameron Davis opened his final round with an eagle and closed with two birdies on his final four holes for a 68 to jump up 16 spots for a share of 45th at 1-under par.