Akron - Australia's Marc Leishman fired a six-under par 64 on Thursday to seize a one-stroke lead in the Bridgestone Invitational with defending champion Tiger Woods four shots back.
Leishman had eight birdies and two bogeys at Firestone Country Club and was one stroke in front of England's Justin Rose, South African Charl Schwartzel and American Ryan Moore.
Rose, the 2013 US Open champion who turned 34 on Wednesday, had five birdies in his five-under 65. Moore also notched five birdies without a bogey while former Masters champion Schwartzel had six birdies and one bogey for his share of second.
"I'm really happy with that number because it wasn't the most in-control round of golf," Rose said. "I kept the scorecard clean with a really good mix of some good iron play and good scrambling when I missed and that's what you have to do around here."
It was a further two strokes back to Americans Patrick Reed and Rickie Fowler, Canadian Graham DeLaet and Italy's Francesco Molinari on 67.
Former world number one Woods, an eight-time winner at Firestone, headed a group on 68 after a roller-coaster round featuring six birdies, two bogeys and a double bogey.
Woods, playing just his third event since back surgery on March 31, three-putted the first from eight feet.
He then hit his drive on the second so far left that it found the short rough to the right of the third hole.
The 14-time major winner recovered with a fairway wood onto the green and two-putted from 50 feet for birdie.
He bounced back from a bogey at the fourth with birdies at the fifth, sixth and eighth.
An errant drive cost Woods a double-bogey six on the ninth but he had two birdies with no bogeys coming in.
Rory McIlroy, making his first start since claiming the third major title of his career at the British Open, headlined a group on one-under 69.
The 25-year-old teed off on 10 and had three birdies in his first 11 holes.
He three-putted the third hole - his 12th - for a bogey and made a double bogey six on the par-four eighth.
McIlroy responded with a closing birdie at the ninth, where he sank a two-footer to end on a good note.
"I didn't want any sort of let down and not just these two weeks, but basically the rest of the season," said McIlroy, who could have a chance to overtake Australian Adam Scott atop the world rankings with a win here.
Scott also opened with a 69 that featured three birdies and two bogeys, while reigning Masters champion Bubba Watson was also in the group of 14 players sharing 14th place at one-under.
Leading first-round scores on Thursday in the $9 million World Golf Championships-Bridgestone Invitational (USA unless noted, par 70):
64 - Marc Leishman (AUS),
65 - Ryan Moore, Charl Schwartzel (RSA), Justin Rose (ENG)
67 - Patrick Reed, Francesco Molinari (ITA), Graham DeLaet (CAN), Rickie Fowler
68 - Jamie Donaldson (WAL), Brandt Snedeker, Keegan Bradley, Sergio Garcia (ESP), Tiger Woods
69 - Branden Grace (RSA), Harris English, David Howell (ENG), Noh Seung-Yul (KOR), Jimmy Walker, Miguel Angel Jimenez (ESP), Rory McIlroy (NIR), Steven Bowditch (AUS), Chris Kirk, J.B. Holmes, Jim Furyk, Bubba Watson, Adam Scott (AUS), Thomas Bjorn (DEN)
70 - Matt Jones (AUS), Thongchai Jaidee (THA), Hideki Matsuyama (JPN), Fabrizio Zanotti (PAR), Gary Woodland, Jason Dufner, Zach Johnson