Martin Kaymer produced an astonishing birdie blitz to win the WGC-HSBC Champions in Shanghai with a closing nine-under 63.
The German, who seemed out of contention early in round three, birdied nine of his final 12 holes to finish three in front of long-time leader Fredrik Jacobson.
There was little sign of what Kaymer was about to produce when he could only par his first six holes on Sunday but a birdie at seven sparked an incredible run that saw him race to a winning total of 20-under.
Jacobson tried bravely to stay with him but his fate was sealed with a bogey at the 17th.
The Swede, who led by one at start of play, eventually finished second at 17-under, one clear of Graeme McDowell.
Rory McIlroy finished tied fourth with Paul Casey and Charl Schwartzel.
Kaymer had started the day five shots behind and rated a 20/1 outsider to come through the pack and land his 10th European Tour title.
Birdies at seven and eight kept his hopes alive but he then missed a short one at nine to remain at 13-under.
However, that proved only a minor blip as he reeled of four birdies in a row from the 10th.
That took him into a tie for the lead for the first time before Jacobson hit back with a 15 foot birdie putt at 12 to join him on 17-under.
Kaymer could only par the long 14th but he made it six birdies in seven holes with another at 15 after a brilliant approach shot to five feet.
Once more Jacobson responded though, his birdie at the par five 14th moving him level again at 18-under and turning the tournament into a two-horse race.
But it was the 26-year-old Kaymer who proved unstoppable.
He kept his foot to the accelerator with a birdie two at 17 and then rolled in a 15 footer for birdie at the last after being forced to lay up with his second.
That put him two clear and with Jacobson bogeying the 17th moments later it was game over.
The bogey five, after a poor wedge, left the Swede three back and a pulled drive at 18 meant there was to be no miracle albatross to tie.
"The way I played golf today was outstanding, especially my back nine," Kaymer told Sky Sports. "The way I putted on the back nine was brilliant, so I'm very happy.
"I was fortunate on a lot of holes I was not in between clubs, always hit good numbers.
"I played aggressive which was nice. I pretty much won the tournament on 18, before that I didn't know if I had won it already or not - because Freddie was still on the golf course.
"It was an OK year before, but now it's a good year."
Earlier, Casey, rather than Kaymer, looked as if he would be the one to charge through for victory.
The Englishman made five birdies in six holes to turn in 31 and was just one behind teeing off at 13 before losing his rhythm.
McDowell overtook him for third place with birdies at 13, 15 and 16.
Masters champion Schwartzel produced the best finish of the day, ending with five straight birdies - one more than he did at Augusta - to leap into a tie for fourth.
McIlroy, who had started with two birdies, joined him there after three birdies in his final four holes. The pre-tournament favourite's chances had ended with bogeys at 11 and 14.
Lee Westwood was the biggest disappointment of the day. The world number two was just four back at start of play but went to the turn in 40 and finished down in 13th after a closing 74.
