Rory McIlroy produced an impressive five-under-par opening round of 67 on the first day of the US PGA Championship at Kiawah Island.
The Northern Irishman has been unhappy with his form in recent majors but produced a bogey-free round.
Swede Carl Pettersson is the leader at six under par after a round of 66.
Tiger Woods shot a three-under-par round of 69 but Englishman Lee Westwood struggled to a three-over-par 75 with Luke Donald on 74.
Gary Woodland, Gonzalo Fernandez-Castano and Alex Noren are a shot off the lead alongside McIlroy, while Dutchman Joost Luiten reached eight under after 14 holes but bogeyed the last four to card a 68.
Of the other morning starters, defending champion Keegan Bradley opened with a 68 to lie four under, Ian Poulter started with a 70, Scot Martin Laird was one under and Darren Clarke was one over after a round of 73. John Daly, who won the tournament in 1991, finished four under.
Later in the day, when the wind made conditions trickier, Open champion Ernie Els bogeyed the first and last hole on his way to shooting 72, while Adam Scott looked to have recovered from his dramatic collapse at Royal Lytham & St Annes with a solid round of 68.
Graeme McDowell is well-placed after four birdies on the back nine left him four under, while Jamie Donaldson is one shot back.
It was a miserable day for Westwood, who shot five bogeys, while world number oneDonald did not fare much better - a double-bogey on the 17th, where he ended up in the water, seeing him finish two over.
It was, however, a welcome return to form for McIlroy. Starting on the 10th in humid conditions, the Northern Irishman birdied his first, fifth and seventh holes before getting a fortunate break on the notorious 17th.
McIlroy, whose chances at last month's Open suffered a blow when a tee shot hit a spectator on the head and his ball flew out of bounds, saw his hooked tee shot bounce off a woman's hip into a bunker and he managed to scramble a par.
McIlroy, who could return to the world number one spot this weekend, also picked up shots at his 11th and 15th holes on the way to only his fourth round in the 60s at a major since his victory at Congressional 14 months ago.
"It's becoming a habit hitting people at majors, so I will try not to do that again," he said. "I think that's my first bogey-free round in a while and it was a great way to start."
Martin Kaymer, who won this tournament two years ago at Whistling Straits shot seven over par, along with Englishman Paul Casey.