Rory McIlroy is delighted to have maintained his winning momentum after overturning a three-shot final-round deficit last night to squeeze past Louis Oosthuizen and win the Deutsche Bank Championship.

The world number one's final-round 67 gave him victory with a 20-under-par total of 264 - one stroke ahead of South Africa's Oosthuizen.

The 2010 British Open champion's late surge was not quite enough as he finished with a 71, and two clear of a resurgent Tiger Woods.

McIlroy, who won the PGA Championship by a record eight shots three weeks ago, had made a blistering start to his final-day challenge with three birdies in his first four holes at TPC Boston in Norton, Massachusetts.

The Co Down man was fortunate to pull back on the fifth hole when his bogey five beat a costly double-bogey by Oosthuizen, who fell further behind when McIlroy birdied the sixth and eighth.

A run of seven straight pars from former Open champion Oosthuizen promised little before birdies on the 13th and 15th hauled him back within a single stroke. After both bogeyed the 17th, pars on the last were enough to give McIlroy the title.

"Delighted to get my fifth win on the PGA Tour, third win this year, second win in the last three events," said the 23-year-old.

"Today was great, going out with a three-shot deficit. I just wanted to get off to a good solid start and maybe put Louis under a little bit of pressure."

He added: "I was able to do that playing the first holes three under, and we both made a couple of mistakes on the fifth hole, but he made a six to my five, so I was able to take advantage of that a little bit.

"It sets me up for a great next couple of weeks, so overall I'm just very pleased" - Rory McIlroy

"I think the good start set me up for a solid back nine. There was a couple of shots on the back nine I... well, I won't take back now, but if I could have then, I would have.

"But I still managed to do enough, and as I said, delighted to get this win, delighted to go to number one in the FedEx Cup. It sets me up for a great next couple of weeks, so overall I'm just very pleased."

McIlroy's triumph lifted him to number one in the FedEx Cup standings and ensured he will have a shot at the $10m prize at the Tour Championship in Atlanta later this month.

Woods carded a strong five-under-par final round of 66 to finish one shot behind Oosthuizen on 18 under - four strokes clear of Phil Mickelson, who also closed with a 66, and Ryder Cup hopeful Dustin Johnson (70).

"My game is starting to come around," Woods said. "I'm pleased with the progress I made this week and really pleased with the way I rolled it. I hit so many good putts all week long, so that's a positive."

Lee Westwood's three-under-par 68 left him with an eight-under total of 276, while Luke Donald and Ernie Els both shot disappointing 70s to finish on five-under 279.