Northern Ireland's Rory McIlroy claimed a share of the BMW Championship lead alongside world number one Jon Rahm and American Sam Burns after the opening round in Baltimore.
The trio carded eight-under-par 64s at Caves Valley Golf Club in the second of the FedEx Cup play-offs.
McIlroy is 28th in the standings, with the top 30 qualifying for next week's season-ending Tour Championship.
Spaniard Sergio Garcia is one shot off the pace in fourth.
Four-time major winner McIlroy hit four birdies on the front nine and eagle on the 16th on his way to carding his lowest first-round score since the Tour Championship in 2020.
"I've been through play-off stretches before where you're always in that lead group," he said.
"You're either one, two or three in the FedEx Cup, and that can sort of take its mental toll. I'm in a position where I need to play well just to play next week.
"There is an element of free-wheeling."
Defending FedEx Cup champion Dustin Johnson is one of 12 players tied in seventh place, while England's Paul Casey bogeyed the 18th to end the day at four under.
Ireland's Shane Lowry and England's Lee Westwood are both at one under.
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