The top-ranked Northern Irishman recovered from some early putting woes to total of 23-under 265 at the season-ending tournament to beat Justin Rose of England, who shot a course-record 62 that included an eagle and eight birdies.
“I just wanted to finish the season the way I thought I deserved to finish the season,”McIlroy said after holing a birdie on 18 and raising his arms in the air in celebration. “You know, I played so well throughout the year and I didn't want to just let it tail off, sort of, timidly. I wanted to come here and finish in style.”
Second-ranked Luke Donald (71) was joint third with 2011 Masters champion Charl Schwartzel of South Africa (68) at 270. Compatriot Louis Oosthuizen (69), the 2010 British Open winner, was a further shot back in fifth place followed by another South African, Branden Grace, who was at 272 after shooting a 68.
The day was supposed to be a duel between McIlroy and Donald, who were joint leaders after the third round. The Englishman took an early two-shot lead when McIlroy bogeyed No. 1 and Donald birdied the following hole.
But Donald three-putted No. 3 to end a run of 102 holes on the Earth Course without a bogey, giving McIlroy a chance. He then had another bogey on No. 12 to fall three back and never challenged after that, missing the green on No. 17 to end his chances.
In the meantime, Rose was climbing up the leaderboard.
He pulled within one of McIlroy with a birdie and then moved ahead with an eagle on No. 14 after his approach shot rolled to within 10 feet. He sank the putt to lead for the first time in the tournament and doubled his advantage when McIlroy three-putted on No. 13. Rose had another birdie before his 60-foot eagle putt came within inches of the cup, settling instead for birdie.
He then had to wait.
“I thought it was going to be good, to be honest,” Rose said of his 275 total. “I caught a glimpse of the board walking to the 18th tee. I saw Rory had gone birdie, birdie and he's putting the squeeze on. But I knew that is what Rory does ... He has a par 5 to play and 18 is no gimmie by any chance. But 16, 17 - not easy holes. It's one birdie for the playoff.”
But rather than let his third bogey end his title hopes, McIlroy bounced back in style.
“I was one behind Justin playing 14 and 3-putting there. I was behind with five holes to play and I thought, you know, while he's 20-under, I'm 18. I've got three good birdie chances,” McIlroy said.
McIlroy just missed an eagle but birdied No. 14. After a great drive on No. 16, he hit a pitching wedge 150 yards to within 20 feet of the pin and sunk the birdie.
“That was big putt to tie the lead,” he said.
At No. 17, McIlroy probably hit the shot of his tournament, landing a 5-iron within a few feet of the pin.
“The most pleasing shot for me on that stretch was the iron shot on 17,” he said. “I think that was big shot. You could easily be a lot right into the bunker and leave yourself a tricky up-and down. I committed to it and hit a great shot and followed it with a great putt for birdie to give myself that cushion going into the last.”
The course played easier Sunday and several players took full advantage. Along with Rose's record score, Sergio Garcia matched the previous record of 64 for the second time in the tournament, and two players had hole-in-ones - Joost Luiten (72) on No. 6 and Stephen Gallacher (66) on No. 4.