|Dell Championship final-round leaderboard|
|-17 J Thomas (US)); -14 J Spieth (US); -13 M Leishman (Aus); -12 J Rahm (Spa), P Casey (Eng); -11 P Mickelson (US), K Na (US), P Reed (US),P Perez (US); -10 B Haas, J Rose (Eng)|
|Selected others: -8 R Fowler (US); -7 D Johnson (US); -5 I Poulter (Eng); -4 J Day (Aus); -2 S Garcia (Spa); -1 M Laird (Sco)|
US PGA winner Justin Thomas held off Open champion Jordan Spieth to win the Dell Championship by three shots.
Thomas, 24, held the overnight lead at 12 under with Marc Leishman, before the Australian moved to 18 under – a two-shot lead – following six birdies.
Spieth then joined leader Leishman, but both made bogeys as Thomas holed birdies on 13 and 15 to move clear.
The American shot a final-round 66 to finish on 17 under, with Spieth second and Leishman third on 13 under.
Spieth, who shot a final-round 67, now leads the FedEx Cup standings with 5,071 points, going into the BMW Championship – the third of four play-off events. Compatriot Thomas is in second spot with 5,044 points.
Paul Casey went around the course at TPC Boston in 70 to end the tournament tied fourth on 12 under, two strokes ahead of fellow Englishman Justin Rose, who shot a 68.
World number one Dustin Johnson, who was the FedEx Cup points leader going into the tournament, finished on seven under, tied for 18th. He is third in the FedEx race with 4,650 points.
In January, Thomas became the youngest man to break 60 on the PGA Tour when he carded an 11-under 59 at the Sony Open in Hawaii, and in June he was the first man to shoot a nine-under-par round at the US Open.
He won his first major in August when he clinched the US PGA Championship – he was embraced by three-time major winner Spieth after coming off the final green.
The Dell Championship was the second of the four FedEx Cup play-off tournaments. The field will be cut from the top 100 points leaders to just the top 70 for the BMW Championship, starting on 14 September.
The final event is the Tour Championship (21-24 September) which features the top 30 points scorers. The winner of 2017 the FedEx Cup will collect a prize of $10m (£7.73m).