Canadian Corey Conners secured his first PGA Tour win with a final round of 66 lifting the 27-year-old to a two-shot win.
Si Woo Kim had held the lead after the first three rounds at the Valero Texas Open, and Conners had a steady start to his final round.
Birdies on the first, and the third, fourth and fifth were cancelled out by bogeys on the next four holes as he reached the turn at a par 36.
But he picked up six shots on the back nine, including a 34-foot putt on the 12th to take the title with a 20 under 268.
Charley Hoffman came in second after carding a 67, followed by Ryan Moore who hit a final day 64 to finish on 18 and 17 under respectively.
Kim tumbled three places down the pack after a round of 72 which included a double-bogey on the par-three third, tying with American Brian Stuard.
Northern Ireland's Graeme McDowell went round in 66 to move up 17 places to tied for seventh, Jordan Spieth fell 14 places to tied 30th after a round of 72, and Scot Martin Laird was six-under for the tournament which was good enough for a share of 36th place.