After the traditional opening ceremony featuring Jack Nicklaus and Gary Player, Adam Scott flew the Aussie flag early. The Queenslander signing for a three under 69 to share the early lead with South African Justin Harding, while his countryman Jason Day struggled again with his back. Before the afternoon groups stacked with big name players started a birdie blitz on Augusta’s back nine.

Tiger Woods had the crowd roaring as he reached three under through 16 holes before a bogey at 17 saw him sign for two under. But it was the 14-time major winner’s fellow Americans Brooks Koepka and Bryson DeChambeau who finished the opening round tied for the lead at six under, with three-time Masters champion Phil Mickelson one back and Ian Poulter and Dustin Johnson a further shot adrift at four under par.

Despite winning three of the last six majors he has teed it up in, Koepka’s decision to change his diet to lose weight was heavily criticised by Golf Channel analyst Brandel Chamblee earlier in the week. Koepka admitting he hadn’t felt 100 percent of late during a press conference on Tuesday when asked about his recent play that has been well below his best.

Bryson DeChambeau watches his ball in flight during the opening round of The Masters at Augusta National. PHOTO: David Cannon/Getty Images.

Koepka brushed aside the controversy after his first round of 66, that included six birdies, five of which came on the back nine.

“Well, I lift (weights) all the time. I lift too many weights, and I'm too big to play golf,” Koepka said when asked of comments on his weight loss. “And then when I lose weight, I'm too small. So, I don't know. I don't know what to say. I'm too big and I'm too small.

“Listen, I'm going to make me happy. I don't care what anybody else says. I'm doing it for me, and obviously it seems to work,” he added looking at the leaderboard in the interview room.

Playing in the final group of the day, the two-time US Open champion missed just two fairways during his first round, but it was his approach play and putting that were responsible for his low round.

“That was probably the best ball‑striking round I've had in a major championship,” Koepka said. “I left myself with a lot of good looks. Hit a lot of good putts. Just didn't make too many.

“I was very impressed with putting the ball in the fairway. I drove it and I shaped it, flighted it, and coming into the greens, controlling the spin, trajectory, everything there was about as good as I could have hit it today.”

RIGHT: Phil Mickelson studies the 15th green on Thursday. PHOTO: Andrew Redington/Getty Images.

Koepka struck a high, towering iron shot close to the pin at the 10th hole, but it was four consecutive birdies beginning with a holed putt from the back fringe at the short par-3 12th that allowed him to surge to the lead.

The 2018 PGA champion appeared as if he might come unstuck at the par-5 15th when he blocked his tee shot into the pine trees right, a fortunate ricochet sending his ball back to the fairway. After an approach long of the green, the American got up and down for another birdie, Koepka missing makeable chances at 16 and 18 that could have given him the lead on his own.

“I get to whatever major championship it is and just when I arrive there, I just get a good feeling,” he said when asked why he performs well at majors. “I don't know – I don't know how to explain it. I'm just dialled in and I'm focused the entire week. I try to relax Monday through Wednesday. I just play nine holes every day just to kind of save some energy, and by that time, I've probably already played the golf course a couple times.”

Like Koepka, DeChambeau made the turn in one under, after a hot and cold front nine that included three birdies and two bogeys. The eccentric 25-year-old matching Koepka’s back nine birdie haul with six of his own, sullied only by a lone bogey at the 14th hole. DeChambeau birdieing the last four holes, with a near hole in one at the 16th and another near hole out for eagle at the par-4 18th, where his iron shot struck the centre of the pin but somehow managed to stay out of the cup.

LEADERBOARD

“What a magical back nine,” DeChambeau said. “Wind started to pick up, right around Amen Corner, and it was tough. It was not easy one bit. But we just stuck to what we knew we should have done, and we did, and was able to execute a beautiful 9‑iron on 12 that kind of jump started my back nine, hitting it to five feet, making that putt got me rolling.

“Only thing we didn't really understand was on 14, we hit a shot, just a little up in the wind and just got really hit by the wind and ended up short rolling back, and that was a big mistake. But other than that, that was the only mistake, except the drive on 17. I'll have to work on that on the range after tonight.”

DeChambeau made good on his promise to the media and was the last player on the driving range at Augusta National after the first round. The former US Amateur champion also attributing his good play on Thursday to a marathon practice session last week at home in Texas after struggling with his wedge play of late.

“Last week I said I'm going to stay here at Dallas National until I figure out what it is on this gear system,” DeChambeau said of working on his ball striking with the help of technology.

“I stayed there for 14 hours on Wednesday hitting shots out there on this system trying to figure out what was happening with the wedges, and we knew it was something in regards to the spin loft curve and us being on the wrong side of the spin loft curve, but we didn't understand how to get it back on the correct side.

“And so after careful observation and some really deep, deep thinking about what's happening and some cool depictions of how the club was moving through the ball, we started to realize it was something we could do with the shafts. And so we went the other way with my previous logic, which I don't really want to give too much about it out, but we went the other way with the way I was previously thinking, and it actually started to work.”

At the other end of the curve when it comes to scientific thinking about golf, Mickelson also nearly made an ace at the iconic 16th hole. The hall of famer’s ball finishing just behind the hole for a tap in birdie, which he followed with a par save at 17 and another birdie at the par-4 18th, punctuated by a fist pump to hold second place ono his own.

RIGHT: Adam Scott leads the Aussie contingent at three under, three back of the lead. PHOTO: Mike Ehrmann/Getty Images.

“I wanted to finish the round off. I hit a poor drive just left on 17 and ended up getting up and down, making about a seven or eight footer for par. And that was a great momentum builder for me to finish off the round,” Mickelson said. “When you have a good round going, you hate to let one leak here or there coming in and I didn't do that today. I finished it off.”

Johnson and Poulter were both happy with their matching rounds of 68 in the windier afternoon conditions. And are positioned well with some potential thunderstorms predicted later in the week that could see players further back struggle to make up ground on the leaders.

Joining Scott and Harding at three under are Jon Rahm, Kevin Kisner and Kiradech Aphibarnrat. The 2013 Masters champion’s round of 69 his best opening round at the event in five years, with bogeys at the 7th and 12th holes offset by five birdies at the 8th, 9th, 15th, 17th and 18th.

“It's a great start on a kind of tricky day, Scott told reporters after the round. “Even though it wasn't windy, I just felt it was very hard to get it near any of the pins through the first seven holes, whether I was just slightly out of position or the pins were just tough.

“One of the things, generally in my career, I'm kind of a slow starter, certainly the last 10 years, I don't jump out of the gates, it seems. So I don't know if this is jumping out of the gates, but it certainly is great,” he added before the afternoon wave of low scores came in, dropping him out of the lead.

MORE ON JASON DAY'S INJURED BACK

Of the other Australians, Jason Day signed for a two under 70 despite visibly struggling with his troublesome back, with Cameron Smith recording the same score on a day that could have gone the other way for the two-time Australian PGA champion.

“I could have let it get away from me a little bit through the round there but I hung in there and made a couple of nice swings towards the end which was nice,” Smith said.

“I didn’t really have my best stuff, I made plenty of clutch putts that kept the momentum going and that was probably the key.”

Rounding out the Aussie contingent was Marc Leishman at even par, who was left with a sour taste in his mouth after three putting the 18th green for a bogey five. The Victorian believing the state of his game suggests a low round isn’t far away.

“It was a pretty good start, you know being under par through nine and then had a pretty good mud ball on 10, where I hit it the one place you can’t hit it, right of that bunker. So that was a double as soon as the second shot finished there really,” Leishman said.

“And then disappointing to three putt the last hole. But felt like I played a lot better than even par, I was in between clubs a lot. Hopefully I can have a little bit better day tomorrow. Even par is not the worst start in the world, but it’s pretty disappointing because I felt like I could have shot five or six under.

“My game’s really good, I’m playing well, I think that’s the most disappointing thing about today, I played good enough to shoot five or six under, more probably. But when you’re having doubles and three putts and a few average shots, it was hard. I know I’m in it.”