Tiger Woods is back at top of the world rankings for the first time in nearly two and a half years after completing an ultimately comfortable two-stroke victory at the Arnold Palmer Invitational.

Defending champion Woods, who will leap above Rory McIlroy at the summit for the first time since the end of October 2010, celebrated his third PGA Tour title of the season after shooting 70 in the final round which was held over after a freak storm hit the Bay Hill course on Sunday.

The American's challenge was boosted by birdies at all par-five holes as he finished on 13 under par overall and two shots clear of England's Justin Rose.

It was playing partner Rickie Fowler who came closest to setting up a thrilling climax with three birdies in six holes, but a disastrous triple-bogey eight at the 16th ended his charge and he was one of four players who finished in a tie for third on eight under overall. 

Northern Ireland's Graeme McDowell finished two over par after a final round 69.

Woods has had to recover from being outside the top 50 in the world at one point and acknowledged he has had to work hard to regain his status.

"It was a by-product of hard work, patience and getting back to playing golf tournaments," he said on Sky Sports 1.

"I've won some golf tournaments in the last couple of years and consequently I've moved up."

When he was asked if he would have to add to his haul of 14 Majors in order to convince the doubters, Woods was typically forthright.

"It's up to them. It's their opinion, I'm very pleased with the way I'm playing," he added.

Woods managed just two holes yesterday in which he extended his advantage from two shots to three and he passed up the chance to open up his lead even further at the third after missing a tricky birdie putt.

The 37-year-old would move to 13 under overall after holing from 12 feet for his third birdie of the week at the fourth moments after Keegan Bradley had briefly reduced his lead to two shots on the same hole.

Woods was in trouble after finding sand on the sixth but a superb up and down allowed him to pick up another shot although he dropped back at the eighth after missing a par putt from 15 feet.

He recovered after teeing off loosely at the ninth but Fowler, who was in the final pairing alongside Woods, managed to cut the gap to three strokes after picking up his first birdie before the turn by rolling in from 30 feet.

The lead was down to two when Fowler again fantastically putted from distance on the par-five 12th, but Woods held his nerve to his obvious delight and those watching by holing from a similar distance to move to 14 under overall.

However, he then failed to find the green and struggled to save par at the 14th, with Fowler taking advantage to sink his 23-foot putt.

While Woods registered his second bogey of the day at the next after finding a greenside bunker, Fowler could only do likewise and his hopes of catching the 14-time Major winner evaporated when he found the water with his approach at the 16th en route to a triple bogey eight.

Woods, however, two-putted for birdie to move three clear of nearest challenger Rose and then par-bogeyed on the final two holes to bring up his eighth victory at the Orlando venue.

It was also a day to remember for Rose, who will move up to number three in the world for the first time following his second place finish at Bay Hill.

The South African-born 32-year-old was the halfway leader although a third round 72 stunted his challenge and he was never in a position to push Woods today after two bogies in his first three holes.

He then picked up four birdies to finish with 70 and 11 under par overall to end his week on a high note.