Zach Johnson admitted he had got lucky after he shot a third-round 60 but still needed a play-off to retain his title at the Texas Open.

The 2007 Masters champion could only fire a 70 yesterday and that saw him finish on 15 under par, alongside fellow American James Driscoll, who closed with an eight-under-par round of 62.

Johnson had won his only previous play-off, at the 2007 AT&T Classic, while put himself in perfect position for a second such win with an approach shot to 10 feet.

Driscoll had a chance to put the pressure back on his rival from 22 feet but his putt broke right, leaving Johnson to successfully claim a birdie and the seventh PGA Tour victory of his career.

"I know it's hard to back up a round like Saturday's, and I certainly didn't play my best on the last day," said Johnson.

"But there were times there when I could have gone further south, and I managed to, whether it was a one-two putt or a difficult shot or taking my medicine when I got myself in trouble, you know, I kind of just remained patient and persevered, so I feel very lucky."