It was a thrilling denouement to a gruelling test over four days at Pinehurst’s fable Number Two course in North Carolina.
The first 14 holes of the final round belonged to McIlroy as he reeled in overnight leader DeChambeau before overhauling him thanks to some superb long-range birdie putts.
However, McIlroy’s touch on the greens completely deserted him down the stretch as he missed from inside three feet on 16 and then four feet on 18, presenting DeChambeau, playing in the group behind, with the opportunity to seal victory.
The champion’s own journey down the 18th was not without trouble, finding wasteland off the tee and then being marooned in a bunker off the front of the green following his second shot.
However, he found the scrambling magic he needed to play a 50-yard bunker shot to inside four feet and calmly roll in for par and win the trophy.
As the popular American celebrated wildly amid raucous scenes around the 18th green, a dejected McIlroy watched on from the scoring room before quickly departing with caddie Harry Diamond.
More to follow.