The in-form American shot an astonishing 13-under-par 59 to finish on a 26-under total of 334 for the five-round event.

It was the third time a 59 has been recorded on the tour, following Al Geiberger's effort in the 1977 Memphis Classic and Chip Beck's round in the 1991 Las Vegas Invitational - but the first time it has been achieved over the final 18 holes of an event.

But the record barely looked on going up the last hole.

At 11-under for his round with a one-stroke lead, Duval ripped a long drive down the middle of the fairway at the par-five 18th, then sent a five-iron approach shot to within eight feet of the pin.

He calmly sank the eagle putt to take his place in the tour's history books.

Flock of birdies on back nine

Duval was only five-under after the first nine holes - but on the back nine he made his move, with birdies at 10, 11, 12, 14, 15 and 16.

"I think at that point I thought about winning," he said. "If I birdied the last hole I would get there."

Duval is in a superb run of form, having recorded all 10 of his PGA Tour victories in his last 28 starts.

Despite Duval's efforts, Steve Pate still had a chance to force a play-off - but he missed a birdie putt at the last and carded a 66 to end a stroke behind on 25-under, one better than John Huston, who also shot 66.

"I played better than everybody but one guy," said Pate. "I guess you could say I was in the wrong place at the wrong time.