Webb Simpson carded a 6-under 64 on Thursday and that gave him a 1-stroke lead after the first round of the WGC - Bridgestone Invitational.
Simpson, the 2012 U.S. Open champion, is playing this event for the first time. He didn't qualify two years ago and last year, he didn't play due to the birth of his second child.
Henrik Stenson is alone in second place on the South Course at Firestone Country Club after opening with a 5-under 65.
Seven-time champion Tiger Woods posted a 4-under 66. He was joined in third place by Ryan Moore, Chris Wood and defending champion Keegan Bradley.
Jim Furyk, Luke Donald and Rickie Fowler, who have all finished runner-up in the last two years, managed 3-under 67s. They share seventh place with Jason Dufner, Bubba Watson and Bill Haas.
Simpson started his opening round with three straight pars from the 10th. He drained a 17-footer for his first birdie of the day at No. 13.
Two holes later, Simpson converted a 20-foot birdie effort. He moved to minus-3 with a birdie at the 17th. He made it two in a row with a 12-foot birdie putt at No. 18.
The 2012 U.S. Open champion birdied the first and second, both from inside seven feet to get to 6-under. Simpson stumbled to a bogey at the third after a poor drive.
Simpson poured in a 30-footer for birdie at six and followed with a short birdie effort at No. 7 to get to 7-under. He missed the green left at the ninth, his last, and that led to a closing bogey.
"Did a lot of things well today and made a lot putts. Just played really good solid golf. Unfortunately, I bogeyed the last hole. I missed a couple left today with some irons shots, so I've got something to work on, even on days like today," Simpson stated.
Stenson birdied the first from five feet out, then rolled in a 31-footer for eagle at the second to quickly get to minus-3. He cruised to eight straight pars from the third.
The Swede stuffed his approach inside two feet at the 11th and kicked that in for birdie. Stenson's tee shot at the par-3 12th stopped within three feet and he knocked that in for birdie to get within one of the lead. He closed with six pars in a row to end one back.
"Birdie-eagle start, you can't get any better than that. Yeah, I feel I'm playing nicely and just doing my job on every hole and not get ahead of yourself, and whenever I missed I managed to save myself a couple of really nice up and downs today, and yeah, I'm very pleased with the start," said Stenson.
Woods nearly holed his approach at the 10th, his opening hole, and kicked in his birdie effort. He found the rough off the 11th tee and that led to a bogey.
The seven-time winner of this event again traded a birdie at the 14th for a bogey at No. 16. Around the turn, Woods made his move.
Woods birdied the first from six feet out. After making birdie at three from inside two feet, he sank an 8-footer for birdie at four to pick up his third birdie in four holes of his second nine. Woods made birdie at eight from seven feet out to end two behind Simpson.
"It's one of those things where I was explaining to you guys yesterday that no matter how I'm playing coming in here, I've played terrible coming in here and I've played really well coming in. And for some reason this golf course, I just see it. It's just one of those venues," said Woods about his record at Firestone. "Luckily over the years I've taken advantage of it. I have played well and I've scored well, and I've won my share of tournaments here."
Newly crowned British Open champion Phil Mickelson mixed five bogeys and three birdies in a round of 2-over 72. That left him tied for 41st after the opening round.
NOTES: Former world No. 1 Rory McIlroy opened with an even-par 70. He had five birdies, three bogeys and a double bogey in his round ... Masters winner and 2011 champ Adam Scott stumbled to a 3-over 73, while U.S. Open titlist Justin Rose posted a 69 ... Hunter Mahan, the 2010 victor, is skipping the event after his wife gave birth to the couple's first child last week.