Bryson DeChambeau triumphed at the U.S. Open for the second time after Rory McIlroy fluffed his lines on Sunday. (More Golf News)
With the pressure on in the final stages of the fourth round at Pinehurst, McIlroy's major hoodoo continued as he bogeyed three of the final four holes.
It meant overnight leader DeChambeau had the chance to put in for par on the 18th and snatch victory by a single point.
McIlroy's last miss, on the 18th, came after he had seen DeChambeau skew a tee shot into the rough, with the Northern Irishman then planting an excellent chip within a couple of feet of the hole.
But the ball rolled agonisingly around the lip as McIlroy dropped another shot, finishing on five under for the tournament.
DeChambeau did not offer McIlroy another chance, drilling a shot out of a bunker and onto the green before sinking a four-foot put to spark huge celebrations in the crowd.
It condemned McIlroy to arguably the most painful defeat of his career, as a fifth major title continues to allude him.
The 35-year-old, who was held off by a single point by Wyndham Clark at last year's U.S. Open, had played brilliantly through the round, and four birdies between the ninth and 13th holes had him on course to win his first major since he triumphed at The Open in 2014.
DeChambeau, on the other hand, could not get going on the back nine, exchanging a pair of birdies with two bogeys, but he steadied himself on the 17th with an excellent drive.
The nerves got to the American, who was the only player to shoot below par in each of the first three rounds, on the 18th, with an awful drive into the rough, yet he regained his composure and, after seeing McIlroy's error, ensured there was to be no more mistakes.
Tony Finau and Patrick Cantlay finished T3 on four under, with Matthieu Pavon rounding out the top five.
