Brandt Snedeker fired an 8-under 63 on Thursday to grab a 1-stroke lead after the first round of the BMW Championship.
Snedeker is the reigning Tour Championship and FedExCup winner, and is already in line to return to East Lake next week. He would be the first player to defend both titles since the FedExCup began in 2007.
Zach Johnson, who won twice this year, opened with a 7-under 64 and is alone in second place at Conway Farms Golf Club.
Tiger Woods, a five-time winner of this event, posted a 5-under 66 and was joined in third place by Charl Schwartzel, Steve Stricker and Kevin Streelman.
Masters champion Adam Scott managed a 4-under 67 and stands alongside John Merrick, Ryan Moore and Nick Watney in seventh place.
Phil Mickelson was 2-over par through 13 holes, but rallied with three consecutive birdies from the 14th for a 1-under 70, which left him tied for 18th.
Defending champion Rory McIlroy struggled to a 7-over 78 and was tied for 66th place. He had a triple-bogey, a double-bogey, four bogeys and two birdies in his round. McIlroy needs a huge rally to make the Tour Championship, as he entered the week 41st on the FedExCup points list.
Woods followed Snedeker's group off the 10th tee. Woods birdied the 10th and 17th to go with seven pars on his first nine.
Around the turn, Woods birdied the second and third, both from inside five feet. After a 3-putt bogey at four, Woods made a 5-footer for birdie at the fifth. He again 3-putted for bogey at six, but followed with another birdie on the seventh.
Woods capped his round with a 22-foot birdie effort at the ninth.
"I'm not exactly real happy. I played well and I just didn't get much out of that round," stated Woods. "It's just reading the greens. The familiarity, I just don't quite have it, and some of the putts are a little bit tricky here and there."
Snedeker started on the back nine Thursday and parred the first three holes. He then ran off seven birdies in a row from the 13th. He started by holing back-to-back shots from off the green at 13 and 14.
The 32-year-old, who has won twice this year, birdied the 15th from seven feet out, then drained a 10-footer for birdie at No. 16. Snedeker holed another birdie effort from the fringe at 17 before rolling in a 5-foot birdie try at 18 to make the turn at minus-6.
Snedeker made it seven in a row at the first when his 18-footer found the bottom of the cup. He parred his next four holes to remain two clear of the field.
At the par-3 sixth, Snedeker converted a 15-foot birdie effort to get to minus-8. He closed with three consecutive pars to lead by one.
"Things were going good, and just wanted to keep giving myself birdie chances. I was rolling the ball so well and seeing the line so well, I knew if kept hitting greens, I'd have some good looks at it," said Snedeker. "I made a couple long putts and got some breaks there and you need that kind of luck on a day like today when the wind is blowing a lot."
Johnson dropped in back-to-back birdie tries at the third and fourth. After four pars in a row, he birdied the ninth to make the turn at minus-3.
The Colonial and John Deere winner followed with birdies at 10 and 11 to get within two at minus-five. Johnson birdied the 15th to keep pace with Snedeker.
At the 18th, Johnson played his third within four feet and ran that in for a closing birdie.
NOTES: Snedeker's run of seven straight birdies matched the best streak on tour this year ... This is the third first-round lead on the PGA Tour for Snedeker ... The first-round leader has won just six of 37 PGA Tour events in 2013 ... All five of Woods' wins at this event came when the tournament was played at Cog Hill.