OAKMONT, Pennsylvania: J.J. Spaun is still new enough to the US Open, and a newcomer to the brute that is Oakmont, that he was prepared for anything Thursday. He wound up with a clean card and a one-shot lead on an opening day that delivered just about everything.

Scottie Scheffler had more bogeys in one round than he had the entire tournament when he won the Memorial. He shot a 73, his highest start ever in a US Open, four shots worse than when he made his Open debut at Oakmont as a 19-year-old at Texas.

Patrick Reed made the first albatross in 11 years at the US Open when he holed out a 3-wood from 286 yards on the par-5 fourth. He finished with a triple bogey.

Bryson DeChambeau was 39 yards away from the hole at the par-5 12th and took four shots from the rough to get to the green.

Si Woo Kim shot a 68 and had no idea how.

“Honestly, I don’t even know what I’m doing on the course,” Kim said. “Kind of hitting good but feel like this course is too hard for me.”

Through it all, Spaun played a steady hand in only his second US Open. He played bogey-free and finished with 10 straight pars for a 4-under 66 on America’s toughest course hosting the major known as the toughest test in golf.

He matched the low opening round in US Opens at Oakmont — Andrew Landry also shot 66 the last time here in 2016 — and it was no mystery. Good putting never fails at any US Open, and Spaun holed five par putts ranging from 7 feet to 16 feet to go along with four birdies.

“I didn’t really feel like I’m going to show a bogey-free round 4 under. I didn’t really know what to expect especially since I’ve never played here,” said Spaun, playing in only his second US Open. “But yeah, maybe sometimes not having expectations is the best thing, so I’ll take it.”

Oakmont lived up to its reputation with a scoring average of about 74.6 despite a course still relatively soft from rain and moderate wind that didn’t stick around for long.

And oh, that rough.

Just ask Rory McIlroy, although he chose not to speak for the fifth straight competitive round at a major since his Masters victory. He had to hack out three times on the fourth hole to get it back to the fairway, and then he holed a 30-foot putt for a most unlikely bogey. He shot 74.

“Even for a guy like me, I can’t get out of it some of the times, depending on the lie,” DeChambeau said after a 73. “It was tough. It was a brutal test of golf.”

The start of the round included Maxwell Moldovan holing out for eagle on the 484-yard opening hole. Toward the end, Tony Finau hit an approach just over the green, off a sprinkler head and into the grandstand, his Titleist marked by green paint of the sprinkler. He saved par.

When the first round ended more than 13 hours after it started, only 10 players managed to break par. That’s one fewer than the opening round in 2016.

Scheffler, the heavy favorite as the No. 1 player in the world who had won three of his last four tournaments by a combined 17 shots, made a 6-foot birdie putt on his second hole. Then he found the Church Pew bunkers on the third and fourth holes, made bogey on both and was never under the rest of the day.

“I made some silly mistakes out there, but at the same time, I made some key putts and some good momentum saves in my round,” Scheffler said. “But overall just need to be a little sharper.”

Spaun, who started his round by chipping in from ankle-deep rough just right of the 10th green, was walking down the 18th fairway when a spectator looked at the group’s scoreboard and said, “J.J. Spaun. He’s 4 under?”

The emphasis was on the number, not the name.

But some of the names were surprising, starting with Spaun. He lost in a playoff at The Players Championship to McIlroy that helped move him to No. 25 in the world, meaning he didn’t have to go through US Open qualifying for the first time.

Thriston Lawrence of South Africa, who contended at Royal Troon last summer, had six birdies in a round of 67.

And perhaps Brooks Koepka can count as a surprise because the five-time major champion has not contended in a major since winning the PGA Championship in 2023, and he missed the cut in the Masters and PGA Championship this year.

He looked like the Koepka of old, muscling his way around Oakmont, limiting mistakes and closing with two birdies for a 68 that left him in a group with the South Korea duo of Si Woo Kim and Sungjae Im.

“It’s nice to put a good round together. It’s been a while,” Koepka said. “It’s been so far off ... but now it’s starting to click. Unfortunately, we’re about halfway through the season, so that’s not ideal, but we’re learning.”

Another shot back at 69 was a group that included two-time major champion Jon Rahm, who went 11 holes before making a birdie, and followed that with an eagle.

“I played some incredible golf to shoot 1 under, which we don’t usually say, right?” Rahm said.

The course allowed plenty of birdies, plenty of excitement, and doled out plenty of punishment.

McIlroy also was bogey-free, at least on his opening nine. Then he three-putted for bogey on No. 1 and wound up with a 41 on the front nine for a 74. Sam Burns was one shot out of the lead until playing the last four holes in 5 over for a 72 that felt a lot worse.

Spaun was not immune from this. He just made everything, particularly five par putts from 7 feet or longer.

“I think today was one of my best maybe putting days I’ve had maybe all year,” Spaun said. “Converting those putts ... that’s huge for momentum and keeping a round going, and that’s kind of what happens here at US Opens.”

Spaun wouldn’t know that from experience. This is only his second US Open, and his ninth major since his first one in 2018. He didn’t have to qualify, moving to No. 25 in the world on the strength of his playoff loss to McIlroy at The Players Championship.

“I haven’t played in too many,” Spaun said “I knew it was going to be tough. I did my best just to grind through it all.”

It was every bit of a grind, from the rough and on the fast greens. Three more days.