BETHESDA, Maryland (AFP) - Tiger Woods sank a tension-packed 20-foot birdie putt on the 16th hole to seize the lead for good and won the PGA National by one stroke over Hunter Mahan on Sunday.

World number one Woods added two routine pars to fire a three-under par 67 final round to stand on 13-under par 267 after 72 holes at Congressional Country Club and claim the trophy at his six million-dollar tournament.

Woods, who won for the 46th time in 49 US PGA events when leading after 54 holes, won his 68th career crown and third title of the year after Bay Hill and Memorial, which also came two weeks before a Major.

Mahan matched the 18-hole course record of eight-under 62 set in Thursday's opening round by fellow American Anthony Kim to seize the clubhouse lead on 268 with Tiger still on the prowl and stalking Hunter across the back nine.

"I don't know what golf course he was playing. I didn't see a 62 out there," Woods said. "He put so much pressure on us. We had to play really well. There was a lot of heat back there."

Woods still shared the lead entering the par-5 16th, where he sent his tee shot into the left rough, put his approach into the right greenside rough and left his chip 20 feet short of the cup.

The 14-time major champion backed away from his putt after being disturbed by a noise, then rammed it into the bottom of the cup to reclaim the lead for good.

Mahan made three birdies on the front nine and had runs of three birdies in four holes to begin and end the back nine, taking his lone bogey at 14 and dropped a 15-foot birdie putt on the 18th to keep the pressure on Woods.

"At that time I wasn't exactly hitting the ball where I wanted," Woods said.

Woods was on his nemesis hole, the par-4 11th. He found weeds and a ditch off the tee and sank a clutch five-foot putt to salvage a bogey, falling into a tie for the lead with Mahan where he stayed until the critical birdie at 16.

The week's five-over par showing by Woods at the 489-yard 11th matched the worst hole for Woods in any non-major tournament in his career, a dubious mark set at Kapalua's first hole in the 2002 Mercedes Championship.

Mahan, whose only US PGA title came at the 2007 Travelers Championship, shared fourth at last week's Travelers and sixth two weeks ago at the US Open.

"I rolled in some putts," Mahan said. "The first three days were a little ugly. I swung great all week but today the putting was great. I'm just really proud of the way I finished."

Kim was third, four strokes off the pace. American Bryce Molder was fourth on 272 with US Open champion Lucas Glover and Brandt Snedeker fifth on 273.

Molder and Paul Goydos claimed British Open berths with their results in a select series of events over the past few weeks while Snedeker also booked a trip to Turnberry in two weeks by virtue of a top-five showing.