World number two Rory McIlroy defied a back injury to stay within three strokes of the lead after round one of the Tour Championship at East Lake Golf Club, Atlanta.
The Northern Irishman started the final FedEx play-off event on -7, a stroke behind last week's BMW Championship winner, Viktor Hovland, and a further two behind Scottie Scheffler.
McIlroy is looking for a record-extending fourth Tour Championship and fourth FedEx Cup trophy, but his chances of achieving this feat were hampered by a back issue leading into the tournament.
Since the conclusion of the BMW last Sunday, the 34-year-old hasn't practiced due to back problems and only managed to hit his first balls when warming up before Thursday's opening round.
The four-time Major winner had a physio walking outside the ropes during the first round in case he needed help, while his caddie, Harry Diamond, was also seen applying some treatment.
Despite being in clear discomfort, McIlroy was able to sign for a level-par 70 to leave him three off the lead and he was delighted to still be in contention after the opening 18 holes.
He said, as quoted by Sky Sports: "I hung in there and I just felt like if I could get through today, it's better than it was yesterday. Hopefully tomorrow is better than it was today and just try to keep progressing.
"The fact that I'm only going to be three off the lead, I'm over the moon about."
McIlroy also delved deeper into exactly what happened to him ahead of the tournament, adding: "I was at the bottom of a squat, a body-weight squat, and my whole lower back spasmed, seized up. I couldn't move.
"I honestly couldn't address the ball this time yesterday. So to get to where I am today is good."
While the immediate concern for McIlroy will be about his chances of winning this week, there is also the small matter of a Ryder Cup at Marco Simone Golf Club, Rome.
The event takes place from 29th September-1st October and the Northern Irishman has already secured one of the six automatic places on Luke Donald's 12-man team, along with Jon Rahm and Hovland.
Donald will be hoping some rest for McIlroy will help ease the back problems and ensure one of his leading stars is fit and raring to go in Italy, as Europe bid to win back the cup.
McIlroy has featured in six Ryder Cups, winning four of those and losing two, with his win-loss-tie record from his 28 matches reading 12-12-4.
Although not at 100 percent, McIlroy is still eyeing a victory this week and he will be hoping the back issue has eased heading into his second round on Friday.
With three shots the gap to the leaders, the 24-time PGA Tour winner can be backed at 15/2 to Win Outright and his impressive record at East Lake always makes him a contender.
There are some quality players he has to catch and there is a three-way tie at the top of the leaderboard, with Collin Morikawa joined by Hovland and Keegan Bradley.
Morikawa shot a superb nine-under-par 61, two better than Bradley's 63, as the American duo catapulted themselves to the top of the standings.
Despite signing for a one-over-par 71, Scheffler is only one off the pace given the starting-strokes system used for this event and he is 10/3 to win for the third time this year.
Englishman Matt Fitzpatrick, who is hoping to get one of the six captain's picks for Europe's Ryder Cup team, signed for a round of 67 to move on to -7 and he is 28/1 to triumph.