Adam Scott lived up to his new world No.1 ranking with a playoff triumph over Jason Dufner on Sunday in the US PGA Tour’s Colonial tournament.

The Australian rolled in a seven-foot birdie putt at the third playoff hole for the victory, cementing his No.1 status in style.

He was playing as the world’s top player for the first time since taking over from injury-idled Tiger Woods on Monday.

The 2013 Masters champion’s hopes of maintaining the top spot took a hit with a first-round one-over 71 at Colonial Country Club on Thursday.

But he clawed his way back, and had gone into Sunday’s final round tied for 11th but just two shots off the lead.

Henrik Stenson, the world No.3 from Sweden who was vying to move past Woods and Scott to seize the top spot, still had a chance after finishing tied for seventh earlier Sunday in the European PGA Championship at Wentworth won by Rory McIlroy.

Based on that finish, Scott needed a top-13 finish to stay atop the rankings.

Scott rolled in a 40-foot birdie putt at the par-four 14th, his seventh birdie of the day giving him a share of the lead at nine-under par along with David Toms.

Toms then bogeyed the 10th to leave Scott alone atop the leaderboard, but Dufner, the 2013 PGA Championship winner, notched the last of his five birdies at the 72nd hole of regulation, draining a 25-footer to get to nine-under tied for the lead with Scott, who couldn’t find another birdie in his last four holes.

Both Dufner and Scott signed for four-under par 66s in the final round for nine-under 271.

They shot matching pars at the first playoff hole – the par-four 18th- and both birdied the second playoff hole, Scott sinking a clutch 14-footer from the fringe at 17 to put the pressure on Dufner to make his four-footer.

American Nicholas Thompson posted a 66 and Sweden’s Freddie Jacobson carded a 67 to share second on 272.

“This is a really special week for me – it was no matter what happened here,” Scott said.

“To kind of fight my way back into this tournament around this golf course, it’s a real honour to win here. It’s a beauty.

“There were some ups and downs for sure on the course, but it was great.

Scott becomes the first player on the PGA tour to have won all four Texas events – the Byron Nelson, Texas Open, Houston Open and now Colonial.

“I was determined. I wanted to have a chance at this one, because I really wanted to win them all here in Texas.”

It was Scott’s 11th US Tour win and he becomes the fifth Australian winner this year on tour.