Final leaderboard: -19 F Molinari (Ita) -18 L Westwood (Eng) -9 L Donald (Eng), R Ramsay (Sco) -8 R McIlroy (NIR) Selected others:-7 T Woods (US), P Casey (Eng) -6 I Poulter (Eng), -2 M Kaymer (Ger) +1 P Mickelson (US)
Westwood (left) congratulates Ryder Cup team-mate Molinari on his victory
Italian Francesco Molinari held his nerve to win the HSBC Champions in Shanghai after a thrilling battle with world number one Lee Westwood.
Molinari had a one-shot lead going into the final day and a fourth-round 67 proved enough to seal victory on 19 under, one clear of England's Westwood.
England's Luke Donald and Scot Richie Ramsay tied for third on nine under.
Northern Ireland's Rory McIlroy was a shot behind Donald and Ramsay, while Tiger Woods finished on seven under.
Woods tied for sixth, 12 shots off the lead, and the former world number one was joined on seven under by Englishman Paul Casey, South Africans Ernie Els and Retief Goosen, Swedish duo Peter Hanson and Frederik Andersson Hed, and Australia's Richard Green.
"Overall I felt like I've been hitting it well and it's just a matter of being patient," said Woods.
Martin Kaymer, who along with Woods, Westwood and Phil Mickelson was vying for the world number one spot, fired a fourth-round 71 to end on two under. Mickelson hit a disappointing 73 and was one-over-par overall.
Two shots behind on the par-five 18th, Westwood had a 25-foot eagle putt to force a play-off, but it stayed left of the hole the entire way.
"It was a little disappointing after hitting a five-iron into the last hole," Westwood reflected.
"I can't believe it got up that slope from where it landed. I expected it to be running down like three or four feet. I just needed the breaks to win and didn't happen."
The Englishman added: "I hit a lot of good shots today and a couple of poor ones. I had a bit of bad luck. It's one of those things.
"I mean, 18-under-par and nine shots clear of third is never too bad.
"It was all about trying to win this week. The rankings come as a consequence of playing well, and I'm playing well and I know I am.
I'm just really proud of the way I played and the way I handled myself
"Today is just very typical of how I've played for the last two years. I was pretty pleased with my short game, the pitch on 16 was in an awful spot, you don't get any harder than that."
It was only Westwood's second strokeplay tournament in three months because of injury, and his first since becoming world number one, and the 37-year-old played the final 43 holes without a bogey.
The 27-year-old Molinari said: "It wasn't easy. I'm just really proud of the way I played and the way I handled myself. Lee is number one in the world, and he was playing some fantastic golf. It was a great finish at the end.
"The [other players] were seven or eight shots behind and we just focused on each other and trying to birdie every hole because we were both playing well and knew that par was not good enough."