Tournament host Tiger Woods saw off defending champion Anthony Kim and held off a last-round charge from Hunter Mahan to win the AT&T National at Congressional Country Club.

Woods collected his third victory of the year, having won Arnold Palmer's event at Bay Hill in March and Jack Nicklaus' Memorial last month, by winning his own tournament by one stroke from Mahan with a final-round three-under-par 67.

It was also his 68th PGA Tour win and the 79th worldwide victory of his career.

Mahan had earlier shot a 62 that matched Kim's course-record round from Thursday and took the American to 12 under, but Woods moved in front with a birdie at the 16th and held onto his lead down the final stretch.

The world number one had been paired with Kim in the final group in Bethesda, Maryland, one-shot leaders at 10 under par over fellow Americans Michael Allen and Cameron Beckman.

Kim got off to a fast start with a birdie at the par-four first hole but had returned to 10 under with a bogey at the fifth, another par four, before Woods took control with back-to-back birdies at the par-four sixth and par-three seventh.

Kim appeared to be blowing his childhood dream of sharing the spotlight in contention with Woods when he bogeyed the eighth to fall three shots back of the 14-time major winner.

Both men sent down birdies, Kim at the ninth, Woods at the 10th but the 24-year-old defending champion was given a lifeline when his hero sent down a bogey five at the 11th, the hole that has been his nemesis on the par-70 Blue Course near Washington DC this week following two bogeys and a double there in previous rounds.

The 16th proved critical as Kim's chance of a successful defence disappeared as he missed from eight feet for birdie while Woods did birdie.

Woods finished at 13 under, a shot ahead of Mahan with Kim, having shot a 71 to finish third on nine under par.