Rory McIlroy looks to be on the return to top form having scored a bogey-free 65 at the opening round of the WGC in Akron.
Tiger Woods also made an excellent start to his bid for an incredible ninth win.
Making his first start since threatening to claim a 15th major title in the Open at Carnoustie, Woods covered his first nine holes in three under par at Firestone Country Club.
Starting from the 10th, the 42-year-old picked up shots on the 11th and par-five 16th before ending the back nine in style, hacking his second shot out of the rough to the front edge of the green and then holing a curling putt from 50 feet for an unlikely birdie.
At three under par, Woods was still four adrift of the early pace set by fellow American Kyle Stanley, who had covered the front nine in 29 and picked up a seventh birdie of the day on the second.
Rory McIlroy was also among the early starters and the 2014 champion covered the back nine in 33 to reach two under par.
After missing just one fairway on the back nine, Woods missed three more in succession after making the turn, but scrambled for par on each occasion and then holed from 15 feet for birdie on the fifth.
At four under par he trailed leader Stanley by three shots, the world number 36 completing a 63, just two shots outside the course record, to set the early clubhouse target.
McIlroy was just two behind after birdies on the second, third and fifth, with Australia's Marc Leishman also five under with two holes to play.
Woods holed from 30 feet for another birdie on the seventh and then produced a brilliant recovery from the rough on the next, slicing his approach around a tree and on to the green.
The birdie putt pulled up inches short and Woods finally paid for some wayward driving when he was unable to scramble par on his final hole after finding a fairway bunker off the tee.
The resulting 66 left the former world number one three shots off the lead and a shot behind McIlroy, who had completed a bogey-free 65 matched by Leishman and Luke List.
Woods made qualifying for the event one of his main goals for the season as the tournament moves from Akron to Memphis next year and scraped in via the world rankings thanks to his tie for sixth in the Open.
"It's a place where I've done it all different ways," Woods told Sky Sports. "I've been around this property for over 20 years and it was nice to see some of the people I've known for years walking a few holes with me and giving me a lot of support.
"I'm going to miss this place."
As for his score, Woods added: "It was a bit of a grind today. I fought hard to shoot the score I shot and really felt like I putted well today."
McIlroy had earlier admitted that playing conditions were as easy as possible and that was borne out as the later starters quickly made inroads on the leaderboard.
Five birdies on the back nine took England's Ian Poulter to the turn in 30 and he was joined on five under by Rickie Fowler, who had covered the front nine in 31 and also birdied the 10th.
World number three Justin Thomas, who will defend his US PGA title next week, had also birdied four of his first six holes, a feat matched by Spain's Jon Rahm.
Poulter, who is in need of good results to move into the automatic qualifying places for the Ryder Cup next month, also birdied the first and second to move into a share of the lead on seven under par.
Fowler and Rahm had also improved to six under, with Masters champion Patrick Reed on four under alongside five-time major winner Phil Mickelson.