Texas - Hunter Mahan fired a final-round 71 on Sunday to win the US PGA Tour's $6 million Houston Open by one stroke over Sweden's Carl Pettersson.
Mahan, who won the elite World Golf Championships Match Play Championship in February, became the first two-time winner on the US tour this year.
The victory will boost the 29-year-old to fourth in the world rankings, sending him into the Masters, the first major tournament of the season that starts Thursday at Augusta National, as the highest-ranked American.
"It feels great," Mahan said. "I'm playing good. I'm glad I'm going to Augusta, it's really a special place and I'm looking forward to going there."
Mahan's one-under 71 at Redstone gave him a four-round total of 16-under 272.
Pettersson also posted a 71 for 273.
South African Louis Oosthuizen, who led by two strokes after the third round, had two double-bogeys in a three-over 75 that left him in third place on 274.
Pettersson, who closed his round with eight straight pars, notched his second runner-up finish of the year, but couldn't get the victory he needed to secure a berth in the Masters.
Three-time major champion Ernie Els also needed a victory to earn an automatic invitation to Augusta. Instead he was poised to miss the Masters for the first time since 1993 after finishing on 10-under.
"It's not going to change my life, either way," Els said. "I've played many out there. It's one of those things."
While the Masters could still offer Els a special invitation, he said he wouldn't accept a last-minute invitation.
"To go through all of this, and then get an invite, I wouldn't take it," he said.
Mahan's two birdies on the day came back-to-back at nine and 10. At the par-three ninth he drained a five-foot birdie putt.
When Pettersson missed his 19-foot birdie attempt at 10, Mahan had sole possession of the lead.
He gave a stroke back with a bogey from a greenside bunker at 14 then saved par from off the green at the par-three 16th, where his pitch on left him a two-footer.
Oosthuizen had opened the door early for those chasing him, starting with a three-putt bogey at the par-four second hole. He bounced back with a 45-foot birdie putt on three, but found a divot with his tee shot at the fifth and ended up missing the green.
After a poor chip he two-putted for a double-bogey.
At the par-five eighth he hit his approach shot into the scrub en route to a second double-bogey.
Leading final round scores on Sunday in the US PGA Tour's $6 million Houston Open (USA unless noted, par-72):
272 - Hunter Mahan 69-67-65-71
273 - Carl Pettersson (SWE) 65-70-67-71
274 - Louis Oosthuizen (RSA) 67-66-66-75
276 - Keegan Bradley 67-69-69-71, Brian Davis (ENG) 68-65-69-74, Phil Mickelson 65-70-70-71, Jeff Overton 69-70-69-68
277 - Bud Cauley 67-69-73-68, James Driscoll 67-66-71-73, J.B. Holmes 68-67-71-71, Cameron Tringale 69-70-70-68
278 - Ernie Els (RSA) 70-69-69-70, Pat Perez 68-69-71-70
279 - Jim Herman 68-70-73-68, John Huh 66-70-70-73, Greg Owen (ENG) 66-69-76-68, Boo Weekley 69-67-70-73
280 - Harris English 69-68-73-70, Bryce Molder 70-70-69-71, John Senden (AUS) 72-65-69-74
- Angel Cabrera (ARG) 65-70-76-70, Marc Leishman (AUS) 70-70-69-72,
Ryan Palmer 71-68-66-76, Scott Piercy 70-70-70-71, Kyle Reifers
68-69-74-70, Henrik Stenson (SWE) 69-68-72-72, Vaughn Taylor
69-67-72-73, Lee Westwood (ENG) 68-70-70-73