DeChambeau, who began the day two shots back of US Open debutant Matthew Wolff, used a mix of jaw-dropping drives and clutch putts to shoot a virtually flawless three-under-par 67 and reach six under for the tournament at Winged Foot.

"I did it. I did it. As difficult as this golf course was presented, I played it beautifully," DeChambeau said.

Wolff, appearing in only his second major and bidding to become the youngest champion since Bobby Jones in 1923, was only one shot back of DeChambeau at the turn.

But the 21-year-old fell apart over a back nine that included two bogeys and a double-bogey.

A fearless DeChambeau, whose final round included an eagle, two birdies and a bogey, attacked at every chance and for his efforts was the only player to break par in the final round as he cruised to a maiden major at his 16th attempt.

The 27-year-old, who re-emerged from the PGA Tour's three-month COVID-19 suspension in mid-June packing serious muscle and hitting a startling distance off the tee, attacked Winged Foot all week like few other golfers can.

So confident in his approach, DeChambeau unleashed his driver on practically every par-4 and par-5 hole as he figured the birdie chances would outweigh the risk that Winged Foot's nasty rough creates.

"I hope that inspires people to say, hey, look, maybe there is a different way to do it," he said.

"Not everybody has to do it my way. I'm not saying that. I'm just saying in general that there are different ways to do things."

DeChambeau celebrates after winning the US Open at Winged Foot. PHOTO: Jamie Squire/Getty Images.

The World No.9 grabbed the solo lead after five holes, hit a perfectly-paced 40-foot eagle putt at the 9th to maintain a one-shot cushion in a tournament that came down to a two-horse race between him and Wolff as they made the turn.

Yet Wolff, who was also trying to become the first player to win the US Open on debut since Francis Ouimet in 1913, bogeyed the 10th and 14th holes before a double-bogey at 16 ended his chances.

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South Africa's former Open Championship winner Louis Oosthuizen (73) birdied the last to finish alone in third place, a distant eight shots back of DeChambeau and one shot clear of American Harris English (73).

Xander Schauffele (74) looked ready to make a back-nine charge after making the turn fresh off back-to-back birdies but the World No.7 made five consecutive bogeys from the 13th and finished in fifth place.

Northern Irishman Rory McIlroy, who finished in a share of eighth place, was almost left in a state of disbelief at DeChambeau's win given his inaccuracy off the tee at a tournament renowned for its thick rough.

Lucas Herbert finished as the leading Australian in a tie for 31st at 12 over after closing with a 74.

- Amy Tennery, Reuters