|-10 C Morikawa (US), K Bradley (US), V Hovland (Nor); -9 S Scheffler (US); -8 A Schenk (US), R Henley (US); -7 M Fitzpatrick (Eng), R McIlroy (NI), J Rahm (Spa)|
|Selected others: -6 T Hatton (Eng); -2 T Fleetwood (Eng)|
Rory McIlroy overcame back issues to fire a level-par 70 and put himself in contention after the first round of the Tour Championship in Atlanta.
The Northern Irishman failed to hit a birdie on the outward nine while dropping two shots.
But four birdies and two bogeys on the back nine put him within three shots of the lead on seven under overall.
Collin Morikawa, Keegan Bradley and Viktor Hovland are in a three-way tie for the lead at 10 under par.
Morikawa, Open champion in 2021, had seven birdies and an eagle in a bogey-free nine-under-par 61 to shoot to the top of the leaderboard.
He was joined by Bradley, who was also bogey-free as he carded a 63, while Hovland, who won last week, shot a two-under 68.
Scheffler carded a one-over 71 to drop to one shot off the lead at East Lake Golf Club.
England’s Matt Fitzpatrick holed an eagle putt on the 18th to ensure he signed for a three-under 67 to lift him level with McIlroy on seven under overall.
McIlroy, who has already qualified for the European team for next month’s Ryder Cup, suffered his back injury while exercising at home on Tuesday and had not practised this week.
“My whole lower back spasmed, seized up. I couldn’t move,” said the world number two. “I honestly couldn’t address the ball this time yesterday. So to get to where I am today is good.”
The PGA Tour’s season-ending tournament uses a stroke-based bonus system, which gives golfers different scores to start their opening round.
The starting strokes range from 10 under – given to FedEx Cup points leader Scottie Scheffler – to level par, given to the last five golfers to qualify for the 30-man event.
Follow Sunday’s final round with live text updates on the BBC Sport website from 18:30 BST.