NEW YORK • Bryson DeChambeau's unorthodox style got major validation on Sunday, as the power-driving "mad scientist" of the PGA Tour claimed the US Open by a definitive six-stroke margin and silenced his sceptics.

Since he unveiled his single-length set of clubs at the start of his pro career, the former physics major has embarked on a one-man mission to revolutionise golf, facing plenty of doubts in a sport where tradition is valued above all else.

His most recent experiment was perhaps his most ambitious yet: a physical transformation that saw the 27-year-old pack on 14kg of muscle with a high-calorie diet and hours spent at the gym during the hiatus this year, in order to add jaw-dropping velocity to his drive.

"I all of a sudden got a lot stronger, worked out every day, been working out every day, and all of a sudden - not because of clubs, but because of me, I was able to gain 20, 25 yards," said DeChambeau after winning his maiden Major title over fellow American Matthew Wolff (75).

He fired a three-under 67, Sunday's only sub-par round, for a six-under 274 total at the formidable Winged Foot layout.

"I kept telling everybody it's an advantage to hit it farther," he added.

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

"Even through the rough, I was still able to manage my game and hit it to correct sides of the greens and kept plugging away.

"My putting was immaculate. My speed control, incredible. You see me out there on the greens with the device trying to control my speed. So many times I relied on science and it worked every single time."

Four-time Major winner Rory McIlroy (75), who finished tied for eighth, told reporters he was initially sceptical that DeChambeau's hard-charging approach would work in the long term, after playing with him at Colonial in June.

"I sort of said, okay, wait until he gets to a proper golf course, he'll have to rein it back in," he said.

"This is as proper as they come, and look what's happened. Yeah, he's got full belief in what he's doing, and it's pretty impressive."

Unlike some of his past experiments - including his now-banned on-course compass and the "side-saddle" putting technique he tried and quickly abandoned in 2017 - DeChambeau said this new approach was here to stay as he aims to add another 5kg before the Masters in November.

"I think I'm definitely changing the way people think about the game.

"There's a lot of people that are going to be hitting it far," said the American, who also plans to try out a 1.2 metre driver next week. That is over 6cm on a club that is already slightly above the average.

His 325 yards off the tee set a record for any US Open champion even though he found only 23 of 56 fairways over four rounds. He also was the only player without an over-par round.

"It's a lot of validation through science," DeChambeau said.

"It definitely is validating I'm able to execute time and time again and have it be good enough to win an Open."

Combating him could be tough. Squeeze fairways thinner and his distance becomes a bigger edge with more people in the deep grass. Make them wider and length is an even greater advantage.

Another key area that has helped him is his skill with the putter.

"The putting has gradually improved over the course of my career. I was dead last when I came out on Tour," he said.

Science again came to his rescue.

"(It) helped me understand how a ball needs to roll in order to give me the best chance to hole a putt.

"Every year I've gotten a little bit better.

"I don't know how much better I can get, but I'm going to keep trying every single week."

REUTERS, AGENCE FRANCE-PRESSE