The start of the year's first major championship was delayed by more than two and a half hours with thunderstorms before DeChambeau quickly made up for lost time with a brilliant seven-under-par 65.

The American enjoys a one-stroke lead over red-hot favourite and World No.1 Scottie Scheffler, with Cam Davis the leading Australian four shots off the pace after opening with a 69.

DeChambeau's blistering round comes four years after he was derided for his infamous boast that he played Augusta National as a par 67.

"Because I can reach all the par-5s in two, no problem," he said back then.

"If the conditions stay the way they are, that's what I feel like par is for me. That's not me being big-headed. I can hit it as far as I want to."

But the 2020 U.S Open champion had only matched his "par 67" once before in 13 rounds since.

He wanted to set the record straight after Thursday's masterclass.

"The comment was definitely misinterpreted," DeChambeau said.

"I said it and I respect people's opinions on it. For me, I have a level of respect for this golf course that's a little bit different than a couple years ago.

"Clearly today was a great test of golf, and I was able to conquer a very difficult golf course today.

Sydneysider Cam Davis was the pick of the Aussies during a weather-hit opening round of the Masters. PHOTO: Getty Images.

"Regarding the 67 comment, you mess up. I'm not a perfect person. Everybody messes up. You learn from your mistakes, and that was definitely one."

Scheffler, with two wins and a second from his past three starts, lived up to his pre-tournament favouritism with his bogey-free 66.

"Mission accomplished for today," he said.

"I did a good job of staying patient today. We kept the golf course in front of us. And, I mean, I executed some really nice up-and-downs to keep the round going."

England's 2016 champion Danny Willett (68) was a surprise package and sitting in a tie for fourth playing in his first tournament in six months following shoulder surgery.

Davis is sharing sixth with Kiwi Ryan Fox at three-under.

Top Australian hope Cameron Smith was happy to notch a one-under 71 after almost a week battling food poisoning.

Five-time champion Tiger Woods is also one-under through 12 holes and whipping the crowd into a frenzy with a stirring challenge at age 48 and with a fused ankle.

Woods and his Australian playing partner Jason Day, who was level with the card, were no chance of finishing their rounds as darkness began to fall in Georgia.

Tiger Woods looks threatening at Augusta National. PHOTO: Getty Images.

Earlier, six-time champion Jack Nicklaus, with his wife Barbara on the bag, joined three-time winner Gary Player and dual champ Tom Watson as thousands of patrons surrounded the first tee to watch them hit the traditional opening shots.

"It's not so easy to put the ball on the tee now, is it?" Player asked the others, before striping one down the fairway.

"Watch out on the left and right," Nicklaus joked before he, too, drove it right down the middle.

It's the sixth consecutive year that the weather has delayed at least some portion of the Masters.

There are 13 players from Saudi-funded LIV Golf in the field this year, including defending champion Jon Rahm, who left the PGA Tour on a half-billion-dollar deal late last year.

Australia's LIV Golf chief Greg Norman was again in the crowd, starting out early watching Rahm, who disappointed with a one-over 73.

Norman said he was back at Augusta watching his LIV contenders, and no doubt would have been thrilled with DeChambeau's charge

– Darren Walton