UPDATE 2-Golf-Tiger wins by a stroke over Mahan at Congressional

* Woods wins by a stroke over Mahan

* Mahan's 62 ties Congressional course record

* Kim slips to third place (adds quotes, details)

By Steve Ginsburg

BETHESDA, Maryland, July 5 (Reuters) - Tiger Woods overcame a course record-equalling performance by Hunter Mahan to win the $6 million AT&T National at Congressional Country Club Sunday.

Tournament host Woods fired a three-under-par 67 to finish at 13-under 267, one stroke better than Mahan, whose final round 62 had brought him to the top of the leaderboard.

But Woods snapped a tie with Mahan by rolling in a 20-foot birdie putt on the par-five 16th before parring the final two holes amid large crowds at Congressional and unseasonably cool weather.

The final round was expected to be a duel between Woods and another fellow American Anthony Kim, but Kim stumbled midway through the final round and finished in third place, four strokes off the pace.

Mahan opened the day six strokes behind the leaders but stormed back into contention by matching the Congressional course record Kim set during first-round play on Thursday.