Unbelievable.

That's the word Rory McIlroy chose to sum up his day and his year last night. The 23-year-old world No.1 finished his 2012 campaign with five birdies to add the DP World Tour Championship to everything else he has achieved.

McIlroy needed something special after Justin Rose had produced a 10-under-par 62 that was not only a course record by two shots, but also the lowest round of his 14-year European Tour career by two.

At one point Rose had gone from six behind to two in front, but McIlroy did not just get the better of his head-to-head with world No.2 Luke Donald, he got the better of Rose, too.

When a 12-foot putt went in on the final green for his fifth successive birdie he had shot a third 66 of the week and on 265, 23 under par, had won by two shots for a double worth more than £1.4m.

The victory – his fifth of the year – earned him almost £840,000, and for topping the European Tour money list, just as he did in America, he collected almost £630,000.

Not that such figures blow his mind any more. The US PGA champion was playing with Titleist clubs for the last time before switching to a deal with Nike worth a reported £156m over the next 10 years.

He said: "I saw Justin make a charge, I heard the cheers, but to finish like that was great. I could not have wished for any better.

"To back up 2011 with another major [like the first by a runaway eight-shot margin] and to be part of an unbelievable story at the Ryder Cup has made it an incredible year.

"Hopefully, I can emulate it or do even better next year."

McIlroy started his burst to the line by chipping to three feet on the long 14th, pitched just as close at the next, then made a 20-foot effort on the following green.

That made him and Rose level and with the par-5 18th to come, McIlroy was favourite. But he did not wait until then to go back in front, a 5-iron to the difficult 17th, more than 200 yards into the wind over water, pulling up only six feet from the flag.

It gave him the comfort of being able to lay up on the last and to get down in a pitch-and-putt was only right and proper.

Rose has the memory of perhaps the putt of the year, from the back of the 18th green. It was estimated at around 100 feet, given the amount of break involved. His ball looked to be stopping on the top of a ridge, but then trickled down to the side of the hole for the easiest of tap-in birdies.

"I knew it was hero or zero there," said the Englishman. "I was one roll away from looking like an idiot."

Donald finished joint third with Charl Schwartzel, five strokes behind McIlroy, his 71 including bogeys at the third and 12th after he had gone a remarkable 102 holes on the course without dropping a shot.

Scott Jamieson finished the best of the Scots, posting a 66 to share 14th place on 275, 13 under. Jamieson officially ended 53rd on the Race to Dubai and is heading to South Africa for the two 2013 Race to Dubai events prior to Christmas.

Stephen Gallacher recorded his third hole-in-one of his career, and the third in Dubai, when he aced the par-3 fourth. But while Gallacher earned the keys to a Mercedes-Benz for an ace earlier this year at the Dubai Desert Classic, this time he picked up two nights stay at the stunning Atlantis Resort.

"There wasn't that many people around except for the wee man here, [11-year old son Jack]," said Gallacher. "Jack did all the celebrating – he was pretty excited."

Gallacher, goes into hospital on Friday for a long overdue operation for a torn cartilage in his right knee. "It's been getting that bad I can't even bend down to read the putts," he added.

Unfortunately, Gallacher's final Race to Dubai standing of 35th sees him miss a spot into next year's Open Championship. However, heading to Muirfield next July is Richie Ramsay (70), who despite dropping three shots over his last three holes, secured his best ever Race to Dubai finish of 26th.

Marc Warren carded a 73 to finish on 278 alongside Ramsay while Paul Lawrie (71) and David Drysdale (69) were tied in 48th spot on four under par. Lawrie ended the year 10th on the money list with earnings of £1,538,907.