The Queenslander was wayward with his opening drive, which led to a bogey, but he fought his way back up the leaderboard with birdies at the 4th, 7th, 14th and 18th holes, to card a three under 67.

He heads into the second round at Atlanta’s East Lake Golf Club one stroke behind a trio of players, who signed for 66 including US Open Champion Dustin Johnson. Also at four under are Japan’s Hideki Matsuyama and American Kevin Chappell, who had four birdies and no bogey in his round.

Playing partners Adam Scott and Jason Day are well placed after round one. PHOTO: Sam Greenwood/Getty Images

Day, who has been battling a back injury since withdrawing from the BMW Championship 12 days ago, said he was pleased with his round despite some poor drives caused by the pain in his back.

“I feel okay. There was a couple of drives out there where the back … just off the top of the transition, felt a bit of a sharp pain in my back,” said Day, who injured his lower back when he bent down to put a tee in the ground during the final round of the BMW. “That's why some of the drives went a little bit … you know. The ones that didn't, I drove it pretty good.

FIRST ROUND LEADERBOARD

“Still not quite there with the driver, but I feel like it’s turning. I'm starting to see the shot go right to left and starting to hit some of the shots going those high, big draws, which is what I like to see.

“To be able to shoot three under in some of the positions that I was in, to get up and down where I was, I'm pretty pleased with.”

The 28-year-old said he was playing through the hurt and will be welcoming a break with open arms after this week.

“I know when it's there, when I get to the top of the swing, as soon as my hips start to unfold and then there's that bit of separation, it just crunches down. It just hurts,” he said.

“In a perfect world, I would love to have two weeks off where I can just really try to settle the back down." - Jason Day.

“It's not 100 percent, but who is 100 percent out here that's playing right now? A lot of guys are playing with some sort of injury. I'm just a little worse off than most guys. But it's not an excuse.

“I've still got to play the golf that needs to be played to try and beat these guys. Unfortunately, they're not going to be sympathetic to me. They're not going to let me go, ‘You know what, your back is sore. We'll give you a couple of shots on the back side.’ It's not going to be like that. I've still got to beat the guys.”

Scott waits with caddie Steve Wiilliams during the first round. PHOTO: Sam Greenwood/Getty Images.

Fellow Queenslander and playing partner Adam Scott could have been sharing fourth place with Day but two late bogies in his round saw him drop out of the top-10 with his under 69.

Scott, even par through nine holes, moved within a short of the lead with birdies at the 11th, 12th and 15th holes. But he missed a six-foot par-saving putt at the 16th and a blocked drive wide of the 17th fairway led to second consecutive bogey.

At the par-5 18th hole, the 36-year-old had to settle for a par despite reaching a greenside bunker in two shots. His bunker escape was a beauty, settling just six feet from the cup but he missed the birdie opportunity before tapping in for par.

Scott sits third and Day is fourth in the FedEx Cup standings and a win for either man at the Tour Championship will see them back sport’s biggest prize cheque for US$10 million.