Tiger Woods looks at his birdie putt on the second hole at the WGC Bridgestone Invitational. Woods scored par on the hole.

Australian Adam Scott birdied four of his last six holes to grab a one-shot lead in the WGC-Bridgestone Invitational first round on Thursday as Tiger Woods made an encouraging return to competition.

Scott, with Woods's former caddie on his bag, fired a sizzling eight-under-par 62 at Firestone Country Club in Akron, Ohio, to take control in the elite World Golf Championships (WGC) event.

"I played extremely solid today," said the 31-year-old Australian who is bidding for his eighth PGA Tour title. "The first 15 holes, I struck the ball beautifully."

Making the most of rain-softened conditions on the heavily tree-lined South Course, Scott delivered a flawless display to end the round a stroke in front of compatriot Jason Day.

American Nick Watney was a further two shots back after returning a 65 but most eyes at Firestone were focused on seven-times champion Woods who carded a 68 on his long-awaited PGA Tour return.

"I was hitting proper shots out there," a smiling Woods told reporters after mixing three birdies with a lone bogey at the par-four 14th. "I hadn't hit the ball like this. This was fun, to be able to hit the ball with that much flush feeling ... and speed I had. It was pretty nice."

Woods, who missed the last two majors because of leg injuries, had not played tournament golf since he pulled out of the Players Championship in May after just nine holes.

"As anybody who's been off and who's been injured, first time back, it's a little nervous to see what happens," said the 35-year-old American, who was followed by huge galleries at Firestone. "But my practice sessions were good so there was no reason why I should be worried out there. I went out there and just let it go, let it rip."

Scott, with Steve Williams on his bag for a fourth tournament since the New Zealand caddie was fired by Woods, covered the back nine in a blistering five-under 30 to surge into the lead.

"Conditions were perfect for scoring ... probably not what we're used to seeing around this course, so it was good to take advantage of that," said Scott.

Scott holed monster birdie putts from 28 feet at the 15th and 17th to take over at the top from early pacesetter Day. "I thought seven under was pretty low but there were so many other good scores," Scott said. "I knew if I could play well and get that putter going, there was a good score out there for me."

Day, one of the hottest players on the PGA Tour this season with seven top 10s in 15 starts, was delighted with the quality of his ball-striking.

British world No. 2 Lee Westwood fired a 67 to end the opening round level with Americans Phil Mickelson, Jonathan Byrd and Keegan Bradley and Japan's Ryo Ishikawa.

Top-ranked Briton Luke Donald and US Open champion Rory McIlroy of Northern Ireland opened with matching 68s. Donald's tidy round featured two birdies while the 22-year-old McIlroy recovered from two early bogeys with two birdies and an eagle at the par-five second.