Justin Thomas held off close friend Jordan Spieth and Marc Leishman in a thrilling shootout to claim a magnificent win at the Dell Technologies Championship.
Thomas displayed the composure that helped him to the PGA Championship title last month as he combined some precision iron-play with clutch putting in a closing 66 that propelled him to a three-shot victory on a riveting final day at TPC Boston.
Spieth ramped up the pressure with a stunning start that saw him get to five under after only four holes in an outward 30, but he and Leishman, who also held the outright lead following a flawless six-birdie front side, lost their way down the stretch as Thomas refused to buckle.
Paul Casey was another to fritter away shots on the back nine as he finished five off the pace, while world No 1 Dustin Johnson slipped from first to third in the FedExCup table after closing with a disappointing 73.
Thomas had to dig deep to stay in touch with Spieth and Leishman in the early stages, but he was up to the challenge as he birdied the second and then got his drive to the short par-four fourth to skip through the front bunker to the fringe, from where he holed from 30 feet for a thrilling eagle.
The 24-year-old followed a good sand save at six with another birdie at the long seventh, although he was one of many players to struggle on the 11th as he pulled his tee shot left of the target and could not get up and down.
But with Spieth and Leishman both faltering, Thomas pounced and set up a birdie at 13 with a superb second to seven feet from the rough that missed the cup by inches, and he converted another sublime wedge in close at the 15th to open up a two-stroke advantage.
Thomas then showed his mettle when he leaked his tee shot right of the 16th green and into thick rough and, although he could not prevent his pitch from rolling eight feet past the pin, he resolutely nailed the return to preserve his lead.
A cast-iron par at 17 actually took him three clear when Spieth bogeyed the last, and Thomas closed out his fifth victory of a memorable year with the minimum of fuss at 18, although he did miss out on a fifth birdie of the day when he missed from inside six feet.
Spieth’s consolation was to surpass Johnson and take over top spot in the FedExCup rankings, but he will be left to rue an erratic back-nine as he failed to build on his electrifying start.
The Open champion clipped a wedge to tap-in range at the first and set up an eagle with a smooth 220-yard approach to eight feet at the second before picking up further shots at each of the next two holes.
Spieth completed a nice up-and-down for another gain at the seventh, but his frustration was evident when he missed makeable chances from inside 15 feet at the next three holes, and he lost ground on his childhood friend when he blocked his second into the trees at the 12th and could only get his speculative pitch halfway to the green.
He did well to limit the damage to a bogey and he then gouged a remarkable wedge from the rough to five feet at the next to get back on track, only to slip back again at the next when he pushed his second to the right of the green and failed to save his par.
Spieth’s 50-footer for birdie at 16 pulled up agonisingly short at 16, and he was aghast that his putt for a three at the next shaved the right edge of the cup before conceding defeat at the last when he thinned his third over the green from a greenside bunker and took three more to get down.
Leishman threatened to spoil the duel between the last two major champions as he cruised to 18 under with his sixth birdie of a sensational front half at the ninth, but the Australian bogeyed the next and three-putted the 11th green before dropping his third shot in a row when he failed to pull off a sand save at 12.
The deflated 33-year-old also bogeyed 17 and 18 to stutter home in 40, although his 70 was enough to secure outright third on 13 under ahead of halfway leader Jon Rahm (68) and Casey, who recovered from three bogeys in five holes with birdies at 16 and 17 to salvage a 70.