Dustin Johnson held his nerve to earn victory in the WGC-HSBC Champions tournament in Shanghai.
Leading by three shots ahead of the final round, the American carded a fine six-under-par 66 to finish at 24 under.
He finished three clear of England's Ian Poulter, who was also six under on Sunday, while Northern Ireland's Graeme McDowell was a further shot behind.
Englishman Justin Rose ended eight behind Johnson while Northern Ireland's Rory McIlroy finished at -15.
"It was a lot of fun out there," Johnson said. "Those guys put a lot of pressure on me. I'm really proud of the way I handled myself."
McDowell is second behind Henrik Stenson on the European Tour's Race to Dubai standings, with Poulter moving up to fourth after he put up a brave defence of the title he won last year.
Poulter, though, was disappointed that he could not have closed the gap further on Swede Stenson, who finished tied 31st, with only two events remaining in Turkey and Dubai in the European Tour's Final Series.
"I'm a little disappointed not to put my hands back on the trophy but Dustin kind of finished the job," said Poulter.
"I'm in great form. The work I've done leading up this run of tournaments has really worked and I couldn't be hitting it any better right now."
Johnson's round started in disastrous fashion as he three-putted the opening hole.
Poulter took advantage by picking up shots at both the first and second, while McDowell birdied the first three holes to earn an early share of the lead with the Englishman.
Birdies at eight and nine got Johnson back into a share of the lead and although Poulter edged in front with a birdie on 12, Johnson birdied 13 and matched Poulter's birdie on the 14 to set up a grandstand finish.
Johnson went ahead when Poulter was unable to get up and down from a greenside bunker on the 15th and the American then chipped in for an eagle two on the 16th after hitting an iron just 10 yards short of the green.
Poulter's birdie putt did not look like going in until it just caught the left edge of the hole, but Johnson now held a two-shot lead on 23 under.
A birdie on the 17th from eight feet extended his lead to three and gave Johnson a welcome cushion playing the 18th, the hole where he drove into the water to run up a double-bogey seven on Saturday.
Unsurprisingly Johnson hit an iron off the tee and laid up with his second, eventually missing a short birdie putt after Poulter and McDowell had done likewise.
It had no effect on the result however, the 29-year-old Johnson claiming his eighth PGA Tour victory and a first prize of more than £856,000.