SHENZHEN, China (AP) -- Ian Poulter still had something to prove this year even after sparking Europe's improbable come-from-behind Ryder Cup victory.
He wanted to take home a stroke-play title--badly.
And Poulter got his wish Sunday after he shot a 7-under 65 to rally from four strokes back to win the World Golf Championships-HSBC Champions at Mission Hills by two shots.
It was the Englishman's second World Golf Championship victory -- he also captured the Accenture Match Play Championship in 2010 -- and his first title of any kind since the Volvo World Match Play Championship in May 2011.
Phil Mickelson (68), Jason Dufner (64), Scott Piercy (65) and Ernie Els (67) finished in a tie for second at 19-under 269.
Lee Westwood and Louis Oosthuizen, the co-leaders overnight, slumped to equal sixth after struggling on the greens and posting identical scores of 72.
Poulter was the star of the European squad at the Ryder Cup this year, making five straight birdies alongside Rory McIlroy to rally the pair past Dufner and Zach Johnson and give the Europeans the point they needed to keep their hopes alive heading into singles play on the final day. The Europeans then came back from a 10-6 deficit to beat the Americans 14 -13 .
Poulter had four wins in four matches at Medinah and improved his career Ryder Cup record to 12-3 -- the highest winning percentage of any European golfer in history.
But he was winless on the PGA TOUR and European Tour this year before Mission Hills.
"I've only been one season without a victory and I certainly didn't want to go another one," the 36-year-old said. "As well as I've played this year, it would have been a disappointment personally to have gone that year without winning."
On a day when five different players topped the leaderboard -- and several others were close -- it was the charismatic Poulter who was the steadiest.
Starting the day four shots back in a share of fourth place, the Englishman surged into the lead after birdying four holes on the front nine and then two more after the turn.
Mickelson and Els tried to stay close, but both wasted opportunities to pull even. Mickelson bogeyed the 12th after missing a 5-footer by an inch, while Els bogeyed the 14th after lipping out a 3-footer and narrowly missed a birdie putt on No. 18.
Ian Poulter wrapped up his first win of 2012 with a gritty par putt on the 72nd hole.
"I know where I came up short," Els said. "But other than that, I played it really nice and struck it nice. Almost made him think there on 18, that putt almost went in."
Defending champion Martin Kaymer looked set to make a final-day comeback for the second straight year, too. Last year, the German birdied nine of his last 12 holes to rally from five shots down in the final round for an unlikely three-stroke victory.
There would be no repeat this year. Starting six shots back, he had five birdies in six holes on the back nine before a disastrous triple bogey on the 17th foiled his chances.
He ended up in ninth place, one stroke behind Australian Adam Scott.
Poulter, meanwhile, calmly sank a 5-foot putt on the 14th hole for birdie and a two-stroke lead. Then, after setting himself up with a difficult 20-foot putt on the tricky 15th hole, he lined up the shot perfectly and dropped it in for birdie.
He was so composed, in fact, he didn't even mind the cameras and mobile phones in the gallery. He's even tried some Chinese to quiet the crowd this week.
"I'm not sure what I'm saying. I'm trying to say `no telephones,'" he said with a laugh. "I backed away a number of times but I was able to refocus knowing that there's probably going to be a few photos taken during the swing."
With Mickelson still in position to catch him, Poulter made a difficult chip shot from the bunker on the 18th and sank a 10-foot putt to seal the victory.
"I saw what he was doing. I was aware," Mickelson said. "So I tried to carve a few shots in to some of the pins and wasn't able to get close enough to them to make birdies to catch him."
It was another Englishman who started the day atop the leaderboard, playing the best golf of anyone in the field. Westwood had putted brilliantly on Saturday, making 11 birdies to shoot a 61--one of the lowest rounds of his career.
He jumped out to a three-stroke advantage Sunday after making two quick birdies on the front nine. But that's when his putting began to break down.
On the par-3 No. 5, he triple-putted for a double bogey. He then missed putts within 10 feet on three consecutive holes before completely unraveling on the back nine with three bogeys, including one on the 15th when he hit a chip shot into a group of photographers.
Oosthuizen, the 2010 British Open champion, was also never able to regain the form that saw him reach 16 under after two rounds--the lowest 36-hole score in a World Championship Golf event since they began in 1999.
He struggled with his putting for a second consecutive day and had four bogeys.
With the $1.2 million winner's paycheck, Poulter moves up to fourth spot in the European Tour's Race to Dubai. The money will also come in handy considering he just treated himself to a new car.
"I've already spent the check last week," he said. "Yes, it was a vehicle and yes, it was very expensive."