Scott needed to make a pressure-filled clutch par from a greenside bunker on the last hole to tie for fifth for the second week running and secure his place in next week's season finale, which offers $US18 million ($A26.1 million) to the winner.

With even the last-placed finisher in the 30-man field in Atlanta receiving $US500,000 ($A727,000), Scott's clutch bunker shot on Sunday was worth at least half a million U.S. dollars as it tipped him into the field in 29th spot, having started the week at 45th.

Australia's former World No.1 became the only player to fight his way through both FedExCup playoffs tournaments in the past two weeks after starting from outside the required ranking number.

"I guess that's the beauty of the FedExCup Playoffs the way they are. You can scratch it around a lot for the year and have a couple good weeks and get heavily rewarded by getting to East Lake and being in that top 30 and all the perks that come with it," Scott said.

He went into last week's FedEx St Jude Championship in Memphis languishing in 77th spot in the FedExCup standings but rose to 45th after finishing joint fifth to earn his BMW Championship spot.

Scott finished at 10-under on Sunday, four shots behind winner Patrick Cantlay, who edged out fellow American Scott Stallings to become the first player in the 16-year history of the FedExCup to successfully defend a Playoffs tournament title after closing with a two-under 69.

Cantlay is also the defending FedExCup champion and will enter the final tournament of the 2021-22 season as second seed behind World No.1 Scottie Scheffler.

Scheffler posted a final-round 70 to tie for third on Sunday at 11 under with fellow American Xander Schauffele (71).

Scott shared fifth with Korean K.H. Lee (65) and Canadian Corey Conners (69) to qualify for the Atlanta finale for the first time since 2019.

"Hopefully stuff to build on this week, and go for it next week with really nothing to lose and head into the next season full of confidence and hopefully keep my head in this place where I feel like I'm one of the best players out here," the 2013 Masters winner said.

Australia's World No.2 Cameron Smith, who sat out this week with hip soreness, will start as the sixth seed at the Tour Championship, which offers a total prize pool of $US33.43 million ($A48.7 million).

"I guess that's the beauty of the FedExCup Playoffs the way they are. You can scratch it around a lot for the year and have a couple good weeks and get heavily rewarded by getting to East Lake." - Adam Scott.

But Lucas Herbert, Marc Leishman and Cam Davis didn't do enough in the BMW Championship to make the season finale.

Herbert's final-round 69 lifted him to joint-15th at seven-under but outside the top-30 overall standings in 43rd spot.

Leishman (70) was tied for 28th at four-under, leaving him 58th in the FedEx rankings, with Davis (71) equal 35th at two-under and 55th in the season-long standings.

Scott’s finish also guaranteed his 10th Presidents Cup appearance for the International side led by Trevor Immelman, with automatic qualifying concluding after the BMW Championship.

Scott will be joined by compatriot Smith, Corey Connors, Sungjae Im, Joaquin Niemann, Joohyung Kim, Hideki Matsuyama and Mito Perira.

Immelman will have four captain’s picks make up his side.