* Simpson wins first title since 2012 U.S. Open
* Birdies three of last six holes to seal victory (Adds detail, quotes)
Oct 20 (Reuters) - Former U.S. Open champion Webb Simpson hit the jackpot in Las Vegas on Sunday, cruising to his fourth career victory on the PGA Tour by a commanding six shots at the Shriners Hospitals for Children Open.
Four ahead of the chasing pack at the start of play, Simpson did not allow his challengers to get any closer than three strokes before tightening his grip on the title with three birdies in the last six holes at the TPC Summerlin.
On another calm and sunny day of ideal scoring conditions in the high Nevada desert, Simpson closed with a five-under-par 66 to post a 24-under total of 260 in the second event of the PGA Tour's 2013-14 season.
"It means the world," Simpson told Golf Channel after sinking a curling 25-footer for par at the last to earn the winner's cheque for $1,080,000 and his first victory on the U.S. circuit since the 2012 U.S. Open.
"This year, I feel like I have gotten better, I just hadn't gotten the win. I was close at Hilton Head but we were working hard and it's just nice to finish the year off with a 'W'."
Simpson, who was embraced by his wife Dowd as he walked off the 18th green, lost out in a playoff with Northern Irishman Graeme McDowell for the RBC Heritage at Hilton Head in April.
Fellow American Jason Bohn bogeyed the last for a 66 to share second place at 18 under with Japan's Ryo Ishikawa (65), with another American, Charley Hoffman, a further stroke back in fourth after firing a joint best-of-the-day 64.
But it was Simpson who once again commanded the spotlight, having led the tournament since Friday's second round.
In pursuit of his first PGA Tour victory since June last year, he made a fast start with two early birdies, draining a 16-footer at the par-four second and a 15-footer at the par-four third to stretch his lead to six shots.
Though Luke Guthrie briefly trimmed that advantage to five with his seventh birdie of the day at the 15th, Simpson coolly sank a 14-foot birdie putt at the par-five ninth to reach the turn at 22 under, six ahead.
Simpson had played rock-solid golf since starting the round and it came as something of a surprise when he three-putted from long range to bogey the par-four 12th for his lead to be briefly cut to three shots over Bohn.
However, he immediately rebounded with a birdie at the par-five 13th, where he sank an eight-footer, to regain a four-stroke cushion.
"I was playing good, solid golf," Simpson said of his form on Sunday before his unexpected slipup at the 12th. "I didn't look at the leaderboards all day but the course was drying out and I knew it was playing tough.
"That three-putt there kind of set me back a little bit but it was nice to birdie 13, and then made a couple more birdies coming in, which was a good feeling."
Simpson struck a brilliant tee shot to just four feet at the par-three 14th but lipped out with his birdie attempt before picking up another shot at the par-four 15th where he pitched to within two feet of the cup from in front of the green.
Another birdie followed at the par-five 16th, where he reached the green in two and comfortably two-putted, and he parred the last two holes to wrap up a commanding win. (Reporting by Mark Lamport-Stokes in Los Angeles; Editing by Gene Cherry/Greg Stutchbury)