As golf's biggest names jostle for the $US10 million ($A14 million) winner's cheque in Atlanta, Scott quietly but steadily climbed into a tie for third place entering the final round.
The 2006 champion compiled a classy third-round five-under-par 65 at Atlanta's East Lake Golf Club to position himself three shots behind Norwegian leader Viktor Hovland.
With his own 65, Hovland turned a halfway share of the lead into a one-shot buffer over American Ryan Gerard (66) as he reached 15 under.
While 2023 champion Hovland is hoping to join grand slam-winning greats Rory McIlroy (2016, 2019, 2022) and Tiger Woods (2007, 2009) as only the third multiple Tour Championship winner, Scott is also playing for history.
At 46 years, one month and 14 days, Scott would become the oldest FedExCup champion, eclipsing Vijay Singh, who was more than a year younger when he won in 2008.
So often cruelling his winning chances on the greens, putting was for once Scott's saving grace on Saturday (Sunday AEST).
The former world No.1 drained 132 yards worth of putts, including near 25-footers for three of his six birdies on the eighth, 13th and 17th holes.
It was Scott's second-best putting round of the year and presented the 2013 Masters champion with an enticing opportunity to land first PGA Tour victory since February, 2020.
"It's a good spot. Within striking distance," said Scott, who has only recorded two bogeys through 54 holes, the fewest of anyone this week.
"It's so congested, though. It's going to need a really great round, I think. There's someone lurking who's going to have that."
Min Woo Lee, Australia's only other player in the elite 30-man field for the $US40 million showpiece, remains an outside hope of becoming the first Tour Championship debutant to win since Xander Schauffele in 2017.
Lee is equal ninth after carding a third-round 66, but will need to reel in a raft of superstars.
At 12 under, world No.1 Scottie Scheffler (66) shares third spot with fellow American Chris Gotterup (67), Scott and Swede Ludvig Aberg (65).
Rory McIlroy was the biggest mover of the day, a round of 63 vaulting the world No.2 from 23rd to joint seventh with Cameron Young (68) at 10 under.
Then it's Lee and American trio Russell Henley (66), Jacob Bridgeman (66) and Sam Burns (67) all at nine under.
The 46-year-old Scott is relishing his crack at another big title.
"I can kind of stick with my game plan of being fairly conservative at least for the front nine," Scott said.
"And if I can execute that, then maybe I've got to start flag hunting a little bit and being a bit more aggressive than I have been.
"But I'll try to play that by ear when I'm out there. It's fun to be in the mix for the Tour Championship and the FedExCup."
