Tiger Woods is poised to extend his remarkable record in World Golf Championships tournaments by winning the WGC-Bridgestone Invitational for an eighth time.

The world No.1 failed to replicate his Friday heroics but his dominance continued at Firestone Country Club as he backed up his second round 61 with a two-under 68 on Saturday to be 15-under and seven shots clear of the field.

Swede Henrik Stenson (67) was the closest pursuer while American Jason Dufner (67) was a short further back going into the final round.

Australia's Masters champion Adam Scott made a small push up the leaderboard with a round of 66 to be tied ninth, but a distant 12 shots behind Woods.

The Queenslander accepted he couldn't catch Woods but had his sights on the five shot deficit to Stenson, with second place still worth $US880,000 ($A990,300) in the lucrative event.

"Anything in the 60s is a good score around here no matter what the conditions are," said Scott.

Woods has already claimed four victories this season and he already 17 career wins in 41 starts in the lucrative elite World Golf Championships series tournaments, though he last won at Firestone in 2009.

With 78 career wins so far, the 14-time major winner is also closing in on Sam Snead's all time US PGA tour win record of 82.

His seven shot buffer in the tournament is his equal fifth biggest career 54-hole lead and the 37-year-old has converted an astonishing 52 of the 56 times he has led or shared the lead after three rounds including 22 of the last 23 times.

"Today was a day where I didn't quite have it, but I scored well. That's the name of the game," Woods said.

"I was just trying to build on my lead somehow and for most of the day I was doing that."

Like Woods, Scott is focussed on sharpening his game for next week's assault on the PGA Championship, the final major of the year.

"I was nearly bogey-free today and it's good to get those rounds in before a major next week where dropped shots are so costly," Scott said.

"The game is sharpening up to where I want it to be, so I'm happy about that. I've done what I needed to do the last couple days.

"I think by next Thursday I can be really sharp."

The other three Australians continued to struggle with Jason Day shooting a 72 to drop to eight-over and a tie for 57th in the 73-man field.

Brett Rumford was 70th at 12-over after a 72 while Australian PGA Championship winner Daniel Popovic shot his best score so far with a 76 to climb off the bottom rung of the leaderboard into 72nd at 22-over.