Koepka and DeChambeau top congested leaderboard with one shot lead over Phil Mickelson on first day of the Masters
Brooks Koepka and Bryson DeChambeau were playing in the final few groups of the day and took advantage of the soft course conditions to break free of a highly congested leaderboard at Augusta National.
At one stage in the day there were nine players tied at the top on three-under-par, but it was the World No.4 and World No.6 who both caught fire on the back nine to lead the field on the opening day.
Bryson DeChambeau almost aced the par-three 16th, chipped in for birdie on 17 and hit the pin with his second shot on the par-four 18th on his way to setting the clubhouse target at six-under par.
"What a magical back nine," DeChambeau said after his round. "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.
"It's obviously my best round out here, 66. I was just looking to shoot something in the 60s this week because I haven't done that yet in my couple times playing here."
He was soon followed by Brooks Koepka, who made four birdies in a row from the 12th and proved once again that he is not a man to doubt when it comes to major championship as he posted the only bogey-free round of the day. He called it one of the best ball striking round he's had in a major championship.
"That was probably the best ball‑striking round I've had in a major championship, I would say," said Koepka. "I left myself with a lot of good looks. Hit a lot of good putts. Just didn't make too many. You know, kind of fell in love with the line there on 16, and 18, actually hit a good putt, just didn't drop.
"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."
Phil Mickelson, who is aiming to become the oldest Masters champion in history this week, birdied three of his last four holes to finish one behind the leaders, with Dustin Johnson and Ian Poulter a shot further back.
Behind them, a group five players sit on three-under, while Tiger Woods and Rickie Fowler are among 10 players at minus 2.
Tiger positive after solid first round 70 as he searches for major number 15
Here’s a stat you might have heard today: Tiger Woods posted a first round 70 for each of his four Masters victories. Today, he added another first-round two-under-par 70 to end up four shots adrift of the leaders.
Woods grabbed his opening birdie on the par-five second with an up and down from the greenside bunker, and would make the turn in one-under after recovering from a dropped shot on the fifth with a birdie on nine.
He gained another shot on the 12th before rolling in a 25-footer for birdie to join the leaders on three-under at the 14th and was positive about his round despite giving a shot back on 17.
“I feel very good,” Woods said after a round that included four birdies and two bogeys. “I feel like I played well today and I controlled my golf ball all day. I've shot this number and won four coats, so hopefully I can do it again.
“I drove it well, hit some good iron shots, speed was good on the greens. And it was tricky, the winds as of right now it puffs up, it goes down, it switches directions, and it's typical of this golf course, it just kind of swirls out there and it's hard to get a bead on the exactly what it's doing at all times.”
Woods is part of a 10-man group on two-under par, which includes Jason Day, Rickie Fowler and Francesco Molinari.
Jason Day receives on-course medical treatment as he suffers with back injury, still shoots 70
It's was a sad and familiar story as Jason Day struggled with a back injury during the first round of the Masters, but it didn't stop him shooting a two-under 70.
The former World No.1 reportedly injured himself picking up his daughter by the putting green before his opening round and ended up receiving treatment after hitting hit tee shot on the second hole.
He has suffered with recurring back issues over the years, and was forced to withdraw from the Arnold Palmer Invitational last month after an MRI revealed he had an 'annular tear'.
Day did decide to keep playing and went on to make birdie on the second, and battled his pain well: Despite visibly struggling to walk properly, Day rolled in more birdies on the eighth, 13th and 16th holes to get to three-under-par. A disappointing three-putt bogey on 17 left him at two-under, but he made his par-putt on the last to end up tied for 11th.
Justin Rose, Jordan Spieth and Paul Casey unexpectedly struggle as Thomas, McIlroy also over par
Justin Rose, Jordan Spieth and Paul Casey all have exceptional records at the Masters over the past few years, but all three players struggled with their games as they finished in the bottom half of the leaderboard on Thursday.
Justin Rose said he wasn't bothered that a World No.1 hasn't won The Masters in a long time earlier in the week, but he's in need of a very strong round on Friday if he wants to challenge for the title.
Rose bogeyed the fifth and dropped three more shots on the seventh, eighth and ninth holes on his way to a three-over 75.
Past champion Jordan Spieth, who has never finished worse than T11 in five Masters starts, also struggled to a 75. He began his round by missing a two-foot putt for par on the first before a double on the par-3 sixth and another bogey on the ninth to go out in 40. He missed a few birdie chances over the next few holes, finally rolling in a putt on 16 to get back to +3.
Playing alongside Spieth, Casey, who was widely tipped to do well this week, added a double bogey at the fifth to droppped shots on one, three and four to find himself five-over after as many holes. It was a score he failed to improve on, bogeying the 12th, 17th and making a double bogey on the final hole to finish with a nine-over-par 81 - which was 15 shots worse than fellow playing partner and first round leader Brooks Koepka and his highest ever career round at the Masters.
Elsewhere, Rory McIlroy had a tumultuous round that included five birdies and six bogeys, but he was quick to find one of his new favourite words, perspective, on the task at hand.
"I mean I felt the course was there. It's soft. There's not much wind. I made five birdies, that wasn't the problem. I just made too many mistakes. And that was the problem. And I'm making mistakes from pretty simple positions, just off the side of the green, 17 and 18 being prime examples of that."
"I think I've sort of been through it all here at this golf course. So it's sort of ‑‑ it's fine. You know you're going to have chances. There's birdie opportunities. I can accept mistakes if I'm trying and it's not a mental error or I haven't got into places, so I can accept some mistakes, but six bogeys out there is a little too many and I'm just going to need to tidy that up over the next few days."
Justin Thomas got off to a good start with a birdie on the third, but bogeyed the fourth and couldn't get back under par for the rest of the day, missing a par-putt on the last to end up tied for 44th with McIlroy and 12 others.
Nicklaus, Player: Ceremonial Tee shots followed by some big opinions
Gary Player didn't hold back during his press conference at the Masters on Thursday after hitting the honourary tee-shot with Jack Nicklaus, and called on the governing bodies to form a ball for professionals that is different from amateurs.
He raised concerns over the future of important golf courses, stating that with the way things are going, there will be a player who one day is able to drive it on the front edge of the 1st green of Augusta National.
"I'd just like to say one thing, and that is we've got to slow this ball down," said Player. "I know I was ridiculed when I said it in front of British TV, BBC 20 years ago, players will hit the ball 400 yards. This is happening regularly. There will be a man standing on the first tee one day and drive it on the front edge of the green.
"So we'd better start thinking, they are going to hit wedges to all the par 5s, and golf courses like St. Andrews, this marvelous golf course, is completely obsolete. They can drive probably six greens. So I don't know where we're going.
"And our leaders of such have got to get together, even though it's a litigious society, they have got to get together now and form a ball for professionals that's different to the amateurs. Let the amateurs have anything they like. We need them to enjoy it. We need more rounds. But we have got to stop this; otherwise, it's going to be a joke, in my opinion."
Jack Nicklaus agreed, and then went on to discuss why he thinks the no-phones policy at Augusta National will be the next thing to change.
New way of watching The Masters is a huge success
The Masters has always been the most limited of all golf tournaments on television, but today marked a historic new beginning.
For the first time, in any event, viewers were able to track and watch every single shot, by every single player, in pretty much real time, as part of a new feature on the Masters.com website.
It's one that proved its worth as main television coverage doesn't start until after the final group has teed off, and means you won't miss a shot all week.