Rory McIlroy felt relieved to have salvaged a five-under 66 from a "scrappy" opening round at the PGA Championship as he and a host of other big names chase Xander Schauffele in Kentucky.

Schauffele leads at Valhalla Golf Club after carding a historic 62 on the first day, with fellow Americans Tony Finau, Sahith Theegala and Mark Hubbard in a tie for second place at six under, three off the lead.

McIlroy is in a large group that also contains Collin Morikawa, sitting four shots off the pace at –5.

Brooks Koepka and Scottie Scheffler are also among the prominent players chasing Schauffele, as they sit on four under after Thursday's action.

It was a more difficult day for Jon Rahm, who shot a one-under 70, but he would have gladly taken that score when he had bogeyed four of his first six holes, while Tiger Woods is at +1 after a 72.

McIlroy's last major win came in 2014 at this tournament and venue. He came into the event in form after two straight wins and remains in contention despite not playing at his peak.

"I rode my luck a little bit," McIlroy said to Sky Sports. "I hope I can drive it like Rory in 2014 over the next few days as I didn't drive it very well [in round one].

"My fairway woods were okay. My scrambling and iron play is coming together, so if I can do all that and hit fairways I am feeling pretty good.

"I sort of felt like it was pretty scrappy for the most part. I don't really feel like I left many out there and I thought I got a lot out of my game.

"Had some good up-and-downs, the chip-in on six. I had a little bit of a scrappy part around the turn there, but not really happy with how I played but I am at least happy with the score."

Masters champion Scheffler will focus on his own game instead of focusing too much on Schauffele's stunning exploits.

"Yeah, I mean, there's nothing I can do," Scheffler said. "Xander went out and played a great round in the morning, and I'm not really going to worry about trying to shoot 9-under. I'm just going to go out and try to hit good shots and play my own game.

"I'd like to clean up a few of the mistakes. I missed two putts I felt like I should have holed, but that's going to happen when the greens get a little chewed up. A couple things I can clean up going into Friday, but overall it was a solid round."

Woods, meanwhile, has accepted inconsistency will be part of his game at this stage of his career, but felt frustrated to end day one over par.

"I am getting stronger for sure," Woods said. "It's just that I don't play a whole lot of competitive rounds.

"Each day is a little bit different. Some days, it's better than others. It's just the way it is. My body is just that way. Some days, it feels great, and others a bit of a struggle.

"I struggled with the speed of the greens. It was a grind. I should have been under par for the day but I am over par and we have a long way to go.

"It is a big-boy golf course. It has gotten longer or maybe I have just got shorter!"

Schauffele sunk nine birdies in a bogey-free round to take the lead. It is just the fourth time a 62 has been carded at a major, with Schauffele matching the record both he and Rickie Fowler equalled in round one of the 2023 US Open.

Branden Grace had previously gone round in 62 at The Open in 2017, though those efforts all came on par-70 courses, whereas Valhalla is a par-71.

Schauffele also beat the course record of 63, set by Jose Maria Olazabal in 2000.