The victory also netted Spieth the $10 million FedEx Cup title, and the 22-year-old ended Jason Day's reign atop the rankings after only one week. With Spieth, Day and Rory McIlroy separated by fractions, this marks the sixth consecutive week the No. 1 ranking has changed hands - the first such streak in Official World Golf Ranking history.
Day and McIlroy dropped to Nos. 2 and No. 3, respectively, while Bubba Watson, Rickie Fowler and Henrik Stenson followed McIlroy. After his second straight withdrawal because of a wrist injury, Jim Furyk dropped two spots from No. 7 to No. 9, allowing Justin Rose and Dustin Johnson to move up to Nos. 7 and 8, respectively. The only other change in the top 10 came at No. 10, where Zach Johnson leapfrogged Sergio Garcia, who did not qualify for the season finale.
Danny Lee capped a career season with a T-2 finish at East Lake, which moved him from No. 53 to No. 36 in the rankings. Paul Casey, who finished T-5 in Atlanta, jumped three spots to No. 23 while rookie Daniel Berger moved up to No. 45 after starting the year at No. 301 in the world.
Elsewhere, Thongchai Jaidee rose 12 spots to No. 32 after his win at the Porsche European Open, while Jamie Donaldson returned to the top 50 at No. 48 after a T-5 finish in Germany. Andrew Loupe secured his PGA Tour card for next season with a win at the Nationwide Children's Hospital Open, a victory that also moved him from No. 528 to No. 293.
Still sidelined for the forseeable future with a back injury, Tiger Woods fell seven spots to No. 299 in the world.