Scott Verplank achieved the highlight of his career when he shot a closing 66 to seal a one-shot victory over Luke Donald in the Byron Nelson Championship.

A former volunteer at his hometown PGA Tour event, where he was given lessons by Nelson who died last year, Verplank resisted challenges from Ian Poulter, Phil Mickelson and Donald to take the title.

"To be from Dallas and win the Byron Nelson tournament is amazing," Verplank told reporters after sinking to his knees in shock when his final putt dropped at the Tournament Players Course. "I know Byron was with me on the 18th green today. There is no way that last putt would have gone in otherwise."

It was the fifth victory of Verplank's 22-year career and first since the 2001 Canadian Open. Donald, who finished second after leading overnight, was rock solid over his first eight holes and led by three shots at one stage, but a double-bogey six on the ninth probably cost him victory.

"I'm obviously very disappointed, but I will look at the positives," Donald said. "I'm encouraged with my game over the last couple of weeks and hopefully that will continue."

He had a chance to force a playoff with a nine-foot birdie putt on the 18th hole.

"I just under read it. One of the few putts I didn't roll well today," he said.

Donald had cut the deficit to a single shot with a birdie on the par-five 16th, and looked set to even things up when Verplank found the bunker with his tee shot on the 17th hole. But he made a sensational sand save, giving both players par.

After birdies on holes three, four and six, Donald held a three-shot lead over Verplank, but the American birdied holes six, seven and eight, and parred the ninth hole as Donald ran into trouble.

He hit his second shot into the tree just left of the green, but his third shot wound up some 40 feet from the cup and he three-putted.

Since his last victory, Verplank has finished second six times and had 30 top-10 finishes.

Mickelson looked like he would mount a major challenge in his first tournament with new swing coach Butch Harmon.

Mickelson came out firing with a four-under 31 on the front nine including two chip-ins for birdie and eagle, but his momentum stalled with only birdies at 13 and 16 and a bogey at the par-four 15th.

Poulter was tied with Mickelson at nine under with a 32 on the front nine and finished third, level with South African Rory Sabbatini and Jerry Kelly who both shot 64 in their final rounds.