Jason Dufner played a bogey-free front nine Sunday to seize a two-stroke lead at the 95th PGA Championship as a host of rivals struggled to stay on his heels.
The 36-year-old American, who squandered a four-shot lead with four holes remaining to lose the 2011 PGA Championship at Atlanta Athletic Club, birdied the par-5 fourth and par-4 fifth as well as the par-4 eighth and sank a seven-foot par putt at the ninth to make the turn on 11-under.
Jim Furyk, the 2003 US Open winner who has not won any title since the 2010 US PGA Tour Championship, birdied the par-3 sixth but made a bogey at the ninth to fall to 10-under.
Furyk began the day with a one stroke lead but led four times after 54 holes last year, including at the US Open, without taking a triumph.
Sweden's Henrik Stenson, trying to become the first male player from his homeland to win a major, was third on eight-under with Masters champion Adam Scott of Australia at six-under.
Furyk and Stenson were the only players to break par each of the first three days at Oak Hill.
Sweden's Jonas Blixt, who began three back, opened bogey-bogey to fall back while Steve Stricker, who was four back, took a bogey at the third.
Australian Adam Scott, the Masters champion who also began four back, had a bogey-birdie start to the round and followed a birdie at the fourth with a bogey at the sixth.
Aussie Jason Day followed on early bogey with seven birdies to reach six-under but closed with three bogeys in a row to finish on three-under 277.
American Scott Piercy, who also followed an early bogey with seven birdies and answered another bogey at 15 with a birdie at 16 only to close with a bogey to take the clubhouse lead on five-under 275 after a final-round 65.
The best final-round fightback to win in tournament history was by American John Mahaffey, who rallied from seven shots down and beat Tom Watson in a 1978 playoff at Oakmont.
South Africa's Tim Clark aced the 220-yard par-3 11th hole with a 3-hybrid, the third hole-in-one of his career and the first in a PGA Championship since 2010.
But British Open winner Phil Mickelson stumbled to a 72 and a 12-over 292 finish.
"I want to just kind of forget these couple of weeks where I really haven't struck it the way I had," Mickelson said. "I didn't play very well. I'm not going to worry about it. I'm going to go home and take a few weeks off."