The Queenslander was confident his ongoing trouble would hold up earlier in the week, telling Golf Australia magazine on the Sunday before Masters week, “It feels alright, it just is what is. It feels pretty good … I will get some physio this week and things should hold up pretty good.”

But Day required treatment two holes into his Masters campaign after apparently feeling discomfort when bending over by the putting green then bogeying the par-4 1st, before managing to birdie the par-5 2nd.

As the round continued the 31-year-old appeared in to be in pain as he walked and bent over to mark his ball on Augusta’s slick greens. However, Day still remained in the tournament hunt despite being in obvious pain, another birdie at the par-5 8th hole getting his score to one under through nine holes.

Birdies at the 13th and 16th then took his score to three under par, tied with countryman Adam Scott on the first page of the leaderboard three strokes behind leaders Brooks Koepka and Bryson DeChambeau.

RIGHT: Day still recorded four birdies during his two under par opening round despite the injury. PHOTO: David Cannon/Getty Images.

Day made his second bogey of the day at the penultimate hole, followed by a par at the last where he awkwardly bent over to replace his ball and collect it from the hole once again.

After signing his scorecard, Day did not speak with the media to comment on the injury. Instead, he  immediately headed for treatment on his back in attempt to be ready to tee off for round two at 10:42am (Augusta time).

Day’s fellow Australian’s offered their support when hearing of his struggles while the major champion was still on course.

“I mean you wouldn’t wish that on anyone, let alone any of the Aussies,” Cam Smith said of Day. “Hopefully he’s alright and he keeps going.”

Scott, who finished his round with the lead before a run by multiple players in the final groups, including Koepka and Bryson DeChambeau who share the lead at six under, was confident Day would know how to manage the injury.

“I mean part of me thinks that that's nothing new, he knows what to do, I mean he seems to have a bad back all the time and plays great,” Scott said. “So I'm sure he knows what he's doing. Hopefully, it's nothing major and he gets through and then he can play the rest of the week.”