Fort Worth, Texas ? Steve Flesch lost his focus on his 37th birthday when he realized he had a two-stroke lead with two holes to play at the Colonial.

That momentary lapse cost him a stroke, but not his second PGA Tour win and a happy No. 37.

Even after missing the 17th green with an approach shot from the middle of the fairway and then needing two chips before making bogey, Flesch won the Colonial on Sunday with an 11-under 269 total, one stroke ahead of Chad Campbell.

Flesch was the only golfer with four straight rounds in the 60s. The left-hander closed with a 3-under 67.

A week after withdrawing from the Byron Nelson Championship because of a sore back and mental fatigue, Flesch was feeling fine wearing the winner’s plaid jacket at Hogan’s Alley.

“I wouldn’t change the way any of it worked out,” Flesch said. “I was tired from playing so many events. Physically, I think I can play every week, but mentally, I can’t. That’s the best decision I’ve made all year.”

Flesch, having already missed three birdie chances of five feet or less, curled in a 16-footer at the 188-yard 16th hole. He was in the middle of the 17th fairway at 12 under, two strokes ahead of Campbell. But he missed the green and left his chip in the rough. Flesch sank a five-footer to salvage bogey. He recovered with a closing par.

“I hit it so well, it would have been a shame not to win,” Flesch said.

Flesch’s other win came at the 2003 HP Classic of New Orleans.

At No. 16, Campbell rolled a 13-foot birdie putt three feet past, then bogeyed 17 after his approach landed in a greenside bunker.

Campbell made a five-foot birdie putt at the 433-yard 18th to finish alone in second after a closing 68.

Stephen Ames’ 64, the best round of the day, put him in third place at 271.