Dustin Johnson fought off Ian Poulter and Graeme McDowell to win the WGC-HSBC Champions in Shanghai
One behind with six to play, the big-hitting American found another gear over the closing holes to card a 66 and post a winning total of 24-under.
That gave Johnson, who played the final six holes in five-under, a three-shot triumph over defending champion Poulter (66), with McDowell (66) a further stroke back in third.
The 29-year-old from South Carolina had led by three shots going into the final day but saw that advantage wiped out in the space of just two holes in overcast conditions at Sheshan International Golf Club in Shanghai.
A three-putt bogey at the first from Johnson, combined with two opening birdies from Poulter, saw the pair tied on 17-under and they were soon joined by the other member of the final group, Graeme McDowell making birdies at the first three holes.
Poulter then birdied the fifth to take the outright lead, only for McDowell to reply on the seventh to join his Ryder Cup team-mate at the top of the leaderboard.
A fourth birdie of the day on the par-five eighth took Poulter ahead once more, although Johnson also picked up his first shot of the day there following an excellent pitch to remain one behind.
Johnson then hit a superb approach to four feet on the ninth to make another birdie and join Poulter in the lead on 19-under, with McDowell a shot behind.
Poulter nudged ahead again at the 12th with a fifth birdie of the day to be one ahead with six to play before Johnson started his decisive charge.
The seven-time PGA Tour winner tied the lead again with a birdie at 13, matched Poulter's birdie on the par five 14th and found himself in front by one as the Englishman bogeyed the 15th.
Johnson seized hold of the tournament with a chip-in eagle at the short par four 16th to momentarily lead by three before Poulter bravely holed a 12 footer for birdie to cut it to two again.
But, now in full flow, Johnson hit a glorious tee-shot at the par three 17th and holed an eight footer for birdie to kick three clear once more.
Having driven into the water down the right to finish with a double bogey on Saturday, Johnson played the 18th conservatively and three shots to the green and two putts ensured a closing par and a first WGC title.
Spain's Sergio Garcia closed with a best-of-the-day nine-under 63 to jump up to fourth while Justin Rose was alone in fifth after a 68.
First-round leader Rory McIlroy (69) shared sixth place with Canadian Graham DeLaet (69).