Top-ranked Jon Rahm, the reigning US Open champion, and fifth-ranked Justin Thomas each fired eight-under par 63s to share the lead after Thursday's opening round of the US PGA Northern Trust.
Spaniard Rahm and US standout Thomas each birdied four of the last five holes on rain-softened greens to share a three-shot lead over American Harold Varner after 18 holes at Liberty National in suburban New York at the first FedEx Cup playoff tournament.
"It probably felt a lot tougher within us than it appeared outside, but at the end of the day, when you're striking it well, it's going to seem easier," Rahm said. "Scores are out there. We just showed it. That's mainly due to the fact of the softness of the greens."
Battling wind gusts up to 25 mph (40 kmh), Rahm delivered a bogey-free round while Thomas made his lone bogey at 15 after finding a fairway bunker.
"It was nice to play well out there in those conditions," Thomas said. "It was very windy, which makes it tough to get the ball close to the hole.
"I had an 8 to 10 inch (20-25 cm) putt I almost missed because of a wind gust. I stayed committed to every shot."
Australia's Adam Scott, Canada's Mackenzie Hughes and Americans Robert Streb, Kevin Na, Tony Finau and Cameron Tringale shared fourth on 67.
Rahm, who captured his first major title in June at Torrey Pines, sank a 24-foot birdie putt at the third and a 22-footer at the 17th.
He had an 11-foot birdie putt at the par-3 fourth, three birdies in a row from seven feet or less starting at the par-5 sixth and two more tap-in birdies on the back nine.
"I can put it in the fairway. From the fairway, you can be aggressive," Rahm said. "You can hit it as low as you want into the wind, and that ball is going to stop on the green.
"If the wind stays up like this, let's not expect everybody to be shooting 8-under every single day because that's just not going to happen."
Thomas returned his putter, nicknamed "Baby", to his bag after two months and performed well on the greens with birdies on four of the first six holes, all on putts of eight feet or less, and added a 10-foot birdie putt to close the front nine.
The 2017 PGA Championship winner sank a 37-foot birdie putt at the par-3 14th and followed his only bogey with three birdies to end the day, all from inside six feet.
"When I have control of my speed like I did today I make a lot more of my putts," Thomas said. "I've done a lot of work the past few months. It was nice to see it pay off."
- Only two pars for Bryson -
World number six Bryson DeChambeau managed only two pars in his round but made nine birdies, five bogeys and two double bogeys in shooting a level par 71.
He's the fourth player since 1983 to make two or fewer pars in a round but finish 18 holes at level par or better, the first to achieve the feat since Australian Jarrod Lyle had a two-under 69 with two pars in round two of the 2011 John Deere Classic.
Scott, the 2013 Masters champion, was a runner-up last week at Greensboro and seeks his first victory since February 2020 at Riviera.
"Good vibes coming in here," Scott said. "Good to have that motivation this week to try and play well and get in that winner's circle."
Defending tournament and playoff champion Dustin Johnson, last year's Masters champion, shot 70 despite a cracked driver.
"For some reason I didn't bring (an extra) one this week," he said. "It's my fault."