Rory McIlroy captured his fifth PGA Tour win and his third of the season with a one-stroke victory in the Deutsche Bank Championship at TPC Boston. He’s also top of the FedEx Cup standings.Rory McIlroy survived a late scare to win the Deutsche Bank Championship at TPC Boston and move into pole position to snatch the $10m FedEx Cup bonus.

The world No 1, who was three strokes behind leader Louis Oosthuizen starting the day, closed with a four under par 67 to win by a shot from the South African on 20 under par and soar to the top of the FedEx Cup standings thanks to his third win of the season.

Three clear with six holes to play, the 23-year old went to the par-five 18th just one in front of the overnight leader, who birdied the 13th and 15th to set up a nail-biting finish in the second FedEx Cup play-off event.

The 2010 Open champion, who failed to produce the fireworks that saw him shoot 63 on Sunday, had a chance to level matters going to the last.

McIlroy bogeyed the 17th after a poor approach, overshooting the green with an attempted flop shot from the left rough. But Oosthuizen clumsily failed to get up and down from the right greenside rough for par,  missed a 10 footer for par there before McIlroy bravely holed from four and a half feet for bogey to remain one shot in front.

The drama continued on the 530-yard, par-five 18th when Oosthuizen split the fairway and McIlroy hit a 320-yard drive through the fairway into a rough-filled hollow and was forced to lay up.

Oosthuizen went for the green in two but sprayed his approach short and right into greenside rough from where he pitched to 12 feet after McIlroy had wedged to 20 feet in three from the fairway.

The Holywood star had a chance to win the title with a bridie but his 20 footer stopped on the lip, leaving Oosthuizen with a slippery putt to force a play-off.

Fortunately for McIlroy’s hopes, his 12 footer slipped past the edge and he signed for a level par 71 to become the 14th overnight leader to fail to win on the PGA Tour this season.

After pocketing a cheque for $1.44m, a relieved McIlroy confessed that it was a case of surviving a nervy finish.

Delighted to win for the fifth time in the US and match Tiger Woods with three wins this year, McIlroy said: “That was all about survival. I didn’t finish it off the way I would have like but I got there in the end.

“I am very happy. It’s the third victory of the year, great to get a victory in these playoffs and it sets me up by putting me in a great position going into the next two weeks.”

Woods eventually shot a 66 to finish two shots behind in solo third on 18 under. But he was always too far back to threathen McIlroy, despite facing a 25 foot eagle chance at the last that could have got him to within one of the winning total.

While it wasn’t McIlroy’s biggest final round comeback to win on the PGA Tour - he was four behind at Quail Hollow in 2010 - the 23-year old superstar produced a grinding performance that confirmed his status as the best player in the world.

He birdied the par five second from three feet and the third from just 12 feet to close within one stroke of the South African, who matched his birdie at the fourth to remain in front on 20 under.

But while McIlroy bogeyed the fifth off a bunkered tee shot, Oosthuizen racked up a double bogey six after hooking his tee shot into a hazard and saw his lead disappear completely.

McIlroy then birdied the sixth after a towering approach to just three and a half feet and followed that with another birdie from 11 feet at the eighth to turn in 32 and lead by two from Oosthuizen and by three from Woods on 20 under with nine to play.

The chasing pack was waiting for the US PGA champion to make a mistake but he was in sensational form and birdied the 12th from 12 feet to go five under for the day and extend his lead to three strokes on 21 under.

Unlike his two runaway major wins, McIlroy hit some loose shots coming down the stretch and was forced to battle hard for victory this time.

Oosthuizen reduced the gap to two shots with five to play when he birdied the 13th from 14 feet to get back to level for the day at 19 under.

McIlroy faced a testing, 35-yard bunker shot at the 14th but splashed out to six feet to retain his two-shot lead, then chipped dead from just off the 15th to save par again as Oosthuizen birdied from 10 feet to close within one again.

Woods was never really a threat, despite finishing two shots behind at the finish to become the first man to earn over $100 in prize money on the PGA Tour.

Six behind at the start, the 14-time major winner made four birdies in his first nine holes before  the birdies dried up on the back nine. Yet while he gave himself a 23 foot eagle chance at the last to get to 19 under and put pressure on the leaders, he missed it and finished third on 18 under after a closing 66.

Padraig Harrington took just 26 putts and birdied three of his last four holes in a four under 67 that helped him finish tied 59th on two over and keep alive his chances of making the Tour Championship

Down eight spots to 56th in the standings, the Dubliner must finish in the top 10 in the BMW Championship at Crooked Stick this week to make the top 30 who go to Atlanta for the season-ending finale.

He played alongside Graeme McDowell but the Ulsterman struggled with his long game again, carding a one-over 72 to finish tied 74th on seven over.

The Portrush star fell to 41st in the FedEx Cup race and now needs at least a top-12 finish in Indiana to progress to the final play-off event.