DeChambeau, who carried a three-shot advantage into Sunday’s final round, survived a wild back nine that saw him lose the lead to four-time major champion McIlroy before executing a perfect bunker shot from 54 yards on the par-4 18th hole to 4 feet.

It came some 15 minutes after McIlroy lipped out a 4-foot par putt for his third bogey over his final four holes, dropping him one shot behind DeChambeau.

"I don’t know what to think; it hasn’t fully sunk in yet. I just want everybody to enjoy it, as well. As much as it is heartbreaking for some people, it was heartbreak for me at the PGA. I really wanted this one," DeChambeau told the assembled media, as quoted by the tournament website.

“When I turned the corner and saw I was a couple back, I said, ‘Nope, I'm not going to let that happen.’ I have to focus on figuring out how to make this happen. I was a little lucky. Rory didn’t make a couple putts that he could have coming in. I had an amazing up-and-down on the last. I don't know what else to say. It’s a dream come true." he added.

The 30-year-old joined a select group of 23 golfers who have won multiple US Open titles, a list that includes Ben Hogan, Bob Jones, Jack Nicklaus, Tiger Woods and fellow Mustang Stewart.

Like Nicklaus and Woods, he also owns U.S. Amateur and NCAA individual crowns to go along with his National Open victories, according to tournament stats.

Fellow American Tony Finau's final-round 67 matched the day’s lowest round and earned him a career-best tie for third with compatriot Patrick Cantlay at 4-under 276.

Cantlay, an eight-time PGA Tour winner still seeking a first major title, fired a 70, while Matthieu Pavon, the 2024 Farmers Insurance Open champion who had never been in a final-round final pairing in a major, posted a 71 for solo fifth at 277.

Hideki Matsuyama, the 2021 Masters champion, finished sixth (278) after a final-round 70. Russell Henley and world no. 2 Xander Schauffele tied for seventh at 1-under 279 after shooting 67 and 68, respectively.