Carl Pettersson posted a 6-under 66 on Thursday to take the lead during the first round of the PGA Championship at a relatively defenseless Ocean Course at Kiawah Island.

With half of the field in the clubhouse, 25 players broke par so far Thursday.

Wind is the big key at the Ocean Course and there has been little to speak of halfway through the round.

Rory McIlroy, the 2011 U.S. Open champion, posted a 5-under 67 and is tied for second with long-hitting Gary Woodland.

Defending champion Keegan Bradley, who won the WGC-Bridgestone Invitational last week, 1991 PGA winner John Daly, former U.S. Open champion Geoff Ogilvy are in at 4-under 68 as is Joost Luiten.

Luiten, a relative unknown from the Netherlands, was going real low at Kiawah Island until four straight bogeys to close his round.

Tiger Woods putted beautifully on Thursday, but it only translated into a 3- under 69.

"I played well today and anything in the 60s is going to be a good start in a major championship, and I'm right there," said Woods, a 4-time PGA Champion.

Woods, and the rest of the field, is chasing a Swede who came to the U.S. late in his teens and is now an American citizen.

Pettersson flew out of the gate on Thursday with a 5-foot birdie putt at the first. He got up and down from a bunker for birdie at the par-5 second, then hit a 5-iron to 25 feet to set up birdie at the fourth.

Just like that, Pettersson was flying out to a share of the lead.

"Obviously getting off to a good start was the key to the round," said Pettersson.

He reached the par-5 seventh in two with a 3-wood, then 2-putted for a birdie. Pettersson made the turn and knocked a 7-iron to a foot to set up an easy birdie at 10.

After five straight pars, Pettersson laid up at the par-5 16th. He wedged his third to seven feet and poured in the birdie putt to get to 6-under par.

Pettersson parred his last two, signed for a 66 and found himself in the lead when Luiten stumbled.

"There really wasn't much wind on the front nine, so I knew I had to keep going low because I figured the wind would get up," said Pettersson. "The wind started blowing a little bit on the back nine, and I carried on solid play, hitting a lot of fairways, hitting a lot of greens and making a few putts. So it was a great day for me."

Pettersson has five PGA Tour wins, including one at this year's Heritage, and a European Tour title. That's a pretty solid career for the 34-year-old, but he owns only two top-10 finishes in major championships.

"You have to be on the whole week because of the setup of the golf courses, and I guess I haven't done that enough," admitted Pettersson. "Maybe I needed a little bit more experience of playing tougher golf courses, and I feel like I do that fairly well nowadays, so hopefully I can contend more."

Ben Curtis, Pat Perez, Ryo Ishikawa, Cameron Tringale and Peter Hanson joined Woods in a tie for eighth.