Adam Scott carded a 5-under 66 on Sunday, then watched several potential challengers fall just short, as he hung on for a 1-stroke win at The Barclays.
Scott claimed his second win of the season at 11-under-par 273. Scott's other victory this year came at the Masters, which was his first career major title.
"I can't believe it to be honest," Scott said about his 10th career victory on the PGA Tour. "I just played a good round today and I came in and really didn't think it had a chance. But obviously things went my way a lot out there, and so happy."
U.S. Open winner Justin Rose (68), five-time champion this season Tiger Woods (69) and Gary Woodland (73) each had a chance to force a playoff with a birdie at the 18th hole, but none of them could convert, and the trio finished a shot off the pace at 10-under 274.
They were joined by Graham DeLaet (65) in second place, while reigning British Open winner Phil Mickelson (65), Jim Furyk (69) and D.A. Points (67) shared sixth at Liberty National Golf Club at 9-under.
Ricky Fowler (70), Nick Watney (69), Matt Every (68) and Jason Kokrak (67) tied for ninth at minus-8.
Woodland and Matt Kuchar shared the lead when play started on Sunday, and both tripped to a bogey at the first to fall to 11-under and into a tie for first with Chappell.
Woodland was the first to pull ahead of the group with a birdie at the fourth, but he then tripped to a double bogey at the fifth after having to take a 1-stroke penalty following an errant drive to fall to 10-under.
He bounced back with a birdie at the seventh to rejoin Chappell and Kuchar atop the leaderboard at 11-under before Chappell claimed the outright lead with a birdie at the eighth.
Kuchar fell apart from there to drop out of contention, starting when he hit his drive at the ninth into the water en route to a triple bogey. He would follow that with bogeys at the 10th, 13th, 15th and 17th before closing with a birdie at the last to finish in a share of 19th place at 5-under.
Chappell, meanwhile, birdied the 10th to move two shots clear of Woodland, but then missed the green at the par-3 11th before 3-putting for a double bogey to fall back to minus-11 and into a tie for the lead with Rose and Woodland.
Rose had birdies at Nos. 4, 6, 12 and 13 to reach 11-under.
Scott, who started the day six strokes behind the overnight leaders, made it a four-way tie for the lead with his birdie at the 16th.
Scott's bogey-free round consisted of three straight gains from the fifth, which he capped with a 14-foot birdie putt at the seventh, and a 10-foot birdie putt at the 14th prior to his tying birdie at the 16th.
He closed with a pair of pars to claim the clubhouse lead.
His competitors started falling behind from there, starting when Chappell bogeyed the 13th to fall to 10-under.
Woodland was next to fall off the pace with a bogey at the 13th and that left just Rose tied for the lead.
The Englishman had a chance to move ahead with a 16-foot birdie putt at the 17th, but he missed slightly to the left and tapped in for par.
At the last, Rose rolled a lengthy birdie effort past the hole, and then pushed his 5-foot par putt wide right for a 3-putt bogey to finish at 10- under.
"I was surprised to see it go five feet by, I mean, I've got to say," Rose said. "But it is what it is. Disappointing way to finish. So in some ways, surprised 11-under-par was where it was in the tournament. Some guys were clearly struggling out there on the back nine, which I guess is a testament to how good a round I put together, but yeah, disappointing to finish that way obviously."
Woods was the next to head to the final hole with a chance to tie the lead after battling back from three bogeys in a six-hole stretch from the 10th with back-to-back birdies at the 16th and 17th to pull within a shot of Scott. But he too failed to convert a long birdie putt after he hit his second shot over the green.
His 19-foot putt from off the green settled inches from the hole.
"I had a chance," said Woods. "I hit a good putt. I thought I made it. It was a little double-breaker and I thought I had it."
Scott's last threat came from Woodland, who had a chance to force a playoff with a 10-foot birdie putt, but his effort rolled past the left side of the cup to hand the win to Scott.
NOTES: The top 100 players on the FedExCup points list at the end of this event qualify for next week's Deutsche Bank Championship ... Among those who dropped out of the top 100 and were eliminated from playing next week were: James Driscoll, Ted Potter, Jr., J.J. Henry, Geoff Ogilvy and Jeff Overton ... Martin Kaymer, Greg Chalmers, Erik Compton, Stuart Appleby and Camilo Villegas all jumped into the top 100 ... With the win, Scott now trails Woods by 162 points for the top spot on the FedExCup points list ... Scott joins Rory McIlroy (2012) and Woods (2007) as players to win a major championship and FedExCup Playoffs event in the same season.