"I've got good feelings around this place," he told www.pgatour.com.

"I'm comfortable, I guess, out there, although the whole thing looks different with ropes and people and grandstands."

Haas certainly looked comfortable, with his eight birdies allowing him a little breathing space over nearest challengers Jonathan Byrd and David Toms.

And the leader attributed his successful start to his putter.

"(Putting well) makes you more comfortable over your iron shots knowing that you can maybe miss this shot and your putter might save you because I just had the good feelings going with it," Haas said.

"It's early, and there's a lot of golf left to play, and I hope it can just work for some of that time."

Byrd had seven birdies and just a single dropped shot on the sixth to finish the day on six under, while Toms scored five birdies, a bogey and an eagle on the par-five seventh to join his American compatriot in second place.

Lucas Glover and Pat Perez are tied for fourth following rounds of five-under 67, while Australia's Stuart Appleby leads a group of five players on four under.

Irish golfer Padraig Harrington is five shots off the leader, sinking four birdies and a bogey for a three-under-par 69.

He is joined by Sergio Garcia, who also picked up four shots with a single bogey on the 17th.

World number two Martin Kaymer is six shots behind Haas after an inconsistent first round where four birdies on the front nine were interspersed with two bogeys.

The German finished with a two-under-par 70 along with Anthony Kim, who followed up an eagle at the seventh with two birdies and two bogeys.

Defending champion Rory McIlroy had a day to forget, however, with a round of three over par which featured five bogeys and two birdies.