Hunter Mahan admitted he had to battle all the way for his first PGA Tour victory after the 25-year-old overcame Jay Williamson in a sudden-death play-off to capture the Travelers Championship in Connecticut.

Mahan finished level with Williamson on 15-under-par after a birdie on the last forced a play-off, before repeating the trick to claim a winner's cheque of just over $1 million.

"I played really well all day," Mahan said. "But Jay was a fighter. He fought the whole day. A couple of times I thought I was going to build up a little bit of a lead and he just made some great shots and some big putts. It was tough. It was so tough."

Mahan started the final round a shot behind Williamson but assumed the lead after carding three birdies in his first 10 holes.

Consecutive bogeys on the 16th and 17th holes saw him fall a stroke behind Williamson before draining a seven-foot birdie putt on the 18th to force the play-off.

"I played the first few holes just awesomely, I played them perfectly," Mahan added. "I couldn't ask to hit any better shots. But that's golf. You have to keep battling. It's 18 holes and you have to keep working and keep working. It's not over until it's over."

Mahan felt his club selection on the 18th was crucial as he hit his approach at the extra hole to within 12 inches.

"I had 147 yards and my caddie John liked the nine and we were both thinking that's one that's going to be close," he said.

"We didn't really want to lay up an eight iron and that wind, it was just everywhere. It was kind of coming into you a little bit sometimes, and then kind of left-to-right.

"And when I backed off and put the club in the bag and started over, the wind went directly where we wanted it. I pulled the trigger and just went for it."

Williamson missed a birdie putt from seven feet in the play-off to hand Mahan victory.

"I was thinking 'all you have to do is knock this in and it doesn't matter what he does and I just hit it low," Williamson said. "I wasn't out of gas emotionally, but I was on empty."

Australian Nick O'Hern finished four strokes back in third after firing a final round 66 that included four birdies over the front nine.

"I hit the ball as well as I could pretty much all day," O'Hern said. "When you're playing well, you feel like you can hole it from the fairway.

"I hit a lot of good shots and a lot of good putts but that's golf."

Vijay Singh finished fourth, with Fijian five strokes off the pace Singh started the first round with a birdie on the first hole and a bogey on the second before claiming a further six birdies to post a five-under-par 65.

Fred Funk finished fifth, while Bo Van Pelt, Tom Lehman and David Toms finished in a three-way tie for sixth.

Ireland's Padraig Harrington finished on two-over-par after a 69 on his final round.