MELBOURNE, November 16, 2013 (AFP) - The Augusta Masters winner leads a group of four -- among them, Fijian former world number one Vijay Singh -- as he bids for back-to-back Australian tournament victories after winning last week's Australian PGA title on the Gold Coast.
World number two Scott fired seven birdies and two bogeys in a five-under 66 to be on 14 under.
"It was a good round out there today for sure, it puts me in really good position for tomorrow," Scott said.
"If there's enough holes with that quality of golf tomorrow, a good score is going to be out there for me.
"I'm giving myself so many opportunities every round. If I do that, I'm going to make a few of them (birdies).
"And if I make a few of them, it'll be hard for the others to have enough."
Singh surged into contention with seven birdies and an eagle in his eight-under 63 to be in a tie for second with Australians Nathan Holman, Nick Cullen and Matthew Griffin.
Singh, the three-time major winner, is searching for his first tournament victory since 2008.
The 50-year-old -- who started the day on two under par, seven behind Scott and Holman -- showed the worth of his recent switch from a long putter to a conventional one, putting impressively during his round.
"The first nine holes was incredible, I thought I could have birdied every hole. I was three under but the first eight holes I didn't hit anything outside of 10 feet," Singh said.
"It's a good feeling, it gets your blood flowing again."
Scott looked on track for a similar round, when he picked up five shots on the front nine, which he ended with three straight birdies.
That took him to 14 under par and a four-shot lead at the turn.
The US Masters champion briefly slipped up, three-putting twice in succession for bogeys on the 11th and 12th holes to slip back to 12 under.
Scott regained his buffer, though, with a comfortable birdie on the par-5 15th and another on the 17th.
Scott will go head-to-head with Singh in the final group on Sunday.
American world number eight Matt Kuchar was a shot further back on nine under after a third round 67.
Australian Scott Strange aced a hole-in-one on the par-3 14th which landed him a six litre bottle of premium wine.
It was slightly downhill and downwind. It pitched probably six yards short and bounced up and ran in," said Strange. who hit a 9-iron 152 metres to achieve the feat.
Leading scores after the third round of the Australian Masters at Royal Melbourne (par-71) on Saturday (Australia unless stated):
199 - Adam Scott 67-66-66
203 - Vijay Singh (FIJ) 72-68-63, Nick Cullen 65-69-69, Matthew Griffin 69-65-69, Nathan Holman 68-65-70
204 - Matt Kuchar (USA) 71-66-67
205 - Ryan Fox (NZL) 68-71-66
206 - Brendon De Jonge (ZIM) 68-70-68
208 - Brody Ninyette 68-70-70
210 - Mathew Goggin 72-71-67, Geoff Ogilvy 71-72-67, Gaganjeet Bhullar (IND) 69-72-69, Jason Scrivener 69-71-70, Matthew Millar 69-70-71
211 - Aron Price 73-71-67, Matthew Guyatt 71-70-70, Clint Rice 69-71-71, Maximillian Kieffer (GER) 67-72-72, Jason Norris 69-69-73
Selected scores:
214 - Cheng-Tsung Pan (TPE) 70-73-71, Jin Jeong (KOR) 73-70-71