Los Angeles - Andrew Landry held off Trey Mullinax in a battle of Americans seeking their first PGA Tour title on Sunday to win the Texas Open by two strokes.
Landry, a 30-year-old Texan, closed with seven consecutive pars but needed to escape a last-hole drama before taking his breakthrough victory with a final-round four-under par 68 to finish 72 holes on 17-under 271 at TPC San Antonio.
"A lot of hard work," Landry said. "Today was a grind."
Mullinax settled for a share of second with countryman Sean O'Hair on 273 with American Jimmy Walker fourth on 274 and two-time major winner Zach Johnson fifth, another stroke adrift.
Landry led by one stroke at the 17th tee and two-putted for par from 53 feet while Mullinax botched his second shot, plunking it 10 feet into a bunker as he tried to reach an elevated green, and made bogey to fall two back entering the par-5 18th.
Mullinax left himself a nine-foot birdie putt while Landry needed to two-putt from 50 feet for the victory but rolled his first putt eight feet past the cup.
Brief tension over a possible two-shot swing ended when Mullinax missed his birdie putt and seconds later, Landry sank his par putt to clinch the title.
"I didn't hit that great a wedge shot," Landry said of his approach. "But I made it in the hole."
The nearest Landry had been to victory was in January when he lost to Spain's Jon Rahm on the fourth playoff hole at the PGA Careerbuilder Challenge.
Landry opened Sunday with three birdies, sinking a 10-foot putt at the first, blasting out from a bunker to three feet to set up a tap-in at the par-5 second and dropping a six-footer at the par-3 third.
After saving a par with an eight-foot putt at the fifth, Landry sent his tee shot at the sixth into a fairway bunker, but blasted onto the green and sank a 10-foot birdie putt.
Landry reached 18-under by starting the back nine with another birdie but took a bogey at 11 after missing the fairway and saw his lead on Mullinax cut to one, setting up the closing thrills.
Mullinax endured a roller coaster start with four birdies and two bogeys in the first eight holes, but began the back nine with back-to-back birdies to stay on Landry's heels.
Chilean 19-year-old Joaquin Niemann, the former world amateur number one making his professional debut, fired his second 67 in a row to finish sixth on 276.
"It's amazing. It's a lot of fun to be standing among the best players in the world on that leaderboard," Niemann said.
"My aim was to be really good. I was having a problem with my putter. This week I make a change and my putting was working really well."
Leading scores after Sunday's final round of the US PGA Tour's Texas Open at San Antonio, Texas (USA unless noted, par 72):
271 - Andrew Landry 69-67-67-68
273 - Sean O'Hair 72-70-65-66, Trey Mullinax 74-68-62-69
274 - Jimmy Walker 71-69-67-67
275 - Zach Johnson 70-65-68-72
276 - Joaquin Niemann (CHI) 72-70-67-67
277 - Ryan Moore 68-67-70-72
278 - Kevin Streelman 74-68-69-67, Andrew Putnam 73-68-68-69, Chris Kirk 73-66-68-71
279 - Ben Crane 72-66-74-67, Billy Horschel 68-71-70-70, Martin Laird (SCO) 73-65-69-72, Richy Werenski 72-68-68-71
280 - Brandt Snedeker 70-72-68-70
281 - David Hearn (CAN) 70-68-73-70, Aaron Baddeley (AUS) 71-71-68-71, Vaughn Taylor 72-68-69-72, Grayson Murray 67-69-72-73
283 - Denny McCarthy 72-67-74-70, Johnson Wagner 72-72-70-69, Nick Watney 70-72-70-71, Retief Goosen (RSA) 73-71-70-69, Chesson Hadley 68-71-71-73, Dylan Frittelli (RSA) 72-71-68-72
284 - JJ Spaun 72-70-71-71, Corey Conners (CAN) 70-74-70-70, Keith Mitchell 70-72-72-70, Jim Furyk 71-73-71-69