By Michael Williams

GolfWRX Staff Writer

American Hunter Mahan made a statement about his place in the golf world, carving out a nervy win 1-shot at the 2012 Shell Houston Open over Swede Carl Pettersson.

Mahan began the day with eight straight birdies before putting up birdie on the par-3 9^th, one of only three birdies for the field on Sunday on that hole. That put Mahan in a tie for the lead at 15-under, and he never looked back. He took sole possession of the lead on the very next hole carding another birdie on the par-4 10^th, moving to 16-under and maintained that level while being chased by a group of players including Pettersson, reigning PGA Champion Keegan Bradley and defending Shell Houston Open Champion Phil Mickelson.

Mahan, whose short game and focus under pressure had been an issue in previous campaigns, showed again that he has put those issues behind him.  He made a key par save at No. 16, putting a flop shot to within 4 feet after airmailing the green with his approach.

After putting up a string of back-nine pars to stay within one shot of the lead, Pettersson split the fairway on No. 18 and then put his approach pin high. His two-putt from 20 feet left him needing a Mahan mistake to get to a playoff. Nursing his slim one shot advantage over Pettersson, Mahan also found the fairway on No. 18. He then hit hit next shot with championship poise, leaving himself a fairly routine two-putt for a 1-under par 71 (16-under 272).

With the fifth win of his career, the 29-year old Mahan achieved several key milestones. He became the first multiple-winner on the PGA Tour in 2012, winning previously at the WGC-Accenture Match Play Championships. He also moved ahead of Johnson Wagner to the top spot in the FedEx Cup Standings. For good measure, Mahan goes into the Masters as the top ranked American player in the Official World Golf Rankings (No. 4).

Third round leader Louie Oosthuizen dropped out of contention when he suffered two double-bogeys on his way to a 41 on the front nine. Oosthuizen managed to steady the ship, but had to settle for a solo 3^rd-place finish, two shots back of the winner.

Defending Champion Mickelson finished with a 71 on Sunday to finish six strokes off the lead at 12-under for the week, and, save for a slightly balky putter, looked as though all phases of his game are ready to begin his quest for a 4^th Masters title.

“I’ve got some good momentum going into next week,” said Mickelson. “I feel like of done all the preparation and now it’s just a matter of getting the touch and feel right for [Augusta}.”

Ernie Els fell short in his bid to earn his way into the Masters. Needing a win to qualify, Els finished with a tie for 12^th place at 12-under 278. Els must now await an invitation from Augusta National to avoid missing the tournament for the first time in 18 years.

Click here for Shell Houston Open discussion