A Fowler chip on the 11th went into the water and he took a drop shot, which also rolled back into the hazard to force him to take another drop.

He found the green and putted in for a triple bogey seven but also dropped a shot on the 12th.

South Africa's Branden Grace briefly led before Fowler birdied the 15th and 17th on the way to victory.

Fowler, 30, finished on 17 under after a three-over-par final round of 74, while Grace finished on 15 under after a two-under 69 on the last day.

"It was a bit of a rollercoaster," said Fowler. "Other than two holes, it was a decent round.

"It was a bad break with the ball rolling back in the water.

"That's what's nice about having a cushion after the first 54 holes."

Fowler survives test of character

Fowler had gone into the dramatic 11th at a rainy Scottsdale with his four-shot overnight lead intact.

However, when he attempted a straightforward pitch, his ball skidded through the green, narrowly missing a bunker before rolling into the water.

He took a drop and walked to the edge of the green to survey the shot, only to look back and see his ball roll back into the water.

Fowler was forced to take another drop - costing him a further shot - and, after leaving himself a testing putt, managed to hole it to a record a triple-bogey seven.

But it appeared to affect his focus as he also bogeyed the next, while Grace knocked in two birdies on the 12th and 13th holes to go into a one-shot lead.

Fowler birdied the 15th as both players were on 16 under heading down the final straight.

There was a two-shot swing in Fowler's favour when Grace hit his drive into the water on 17, which led to a bogey five, while the American birdied the same hole, before a par on the 18th gave him victory.