DeChambeau had similar sentiments.

“Yeah, it’s a completely different test,’’ said DeChambeau, who noted he had some equipment issues to work out in light of the cooler temperatures and the golf ball not “compressing’’ as much. “I didn’t get any practice in it, and I didn’t really play much in the rain. It’s a difficult test out here. Something I’m not familiar with. I never grew up playing it, and not to say that that’s the reason; I finished eighth at St Andrews (in 2022). I can do it when it’s warm and not windy.’’

That certainly wasn’t the case Thursday. After relatively mild conditions during the practice rounds, players arrived to rainy conditions and a different wind, one that was coming out of the South. That meant the opening holes—typically the easiest part of the course—played far different.

McIlroy actually managed them well enough, following an opening bogey with a birdie. But at the eighth hole, known as the postage stamp, the fine line of links golf came into play.

The four-time major winner hit a tee shot that appeared fine, but was simply too close to the edge of the green, rolling off into a bunker. From there, McIlroy hit his shot out only to to see it roll back in. That led to a double-bogey 5.

“But still, felt like I was in reasonable enough shape being a couple over through nine, thinking that I could maybe get those couple shots back, try to shoot even par, something like that,’’ McIlroy said. “Then hitting the ball out of bounds on 11, making a double there. Even though the wind on the back nine was helping, it was a lot off the left. I was actually surprised how difficult I felt like the back nine played. I thought we were going to get it a little bit easier than we did.’’

McIlroy was unable to add any birdies and had bogeys at the 15th and 18th holes to shoot his highest score since a 79 in the first round of the 2021 Players Championship at TPC Sawgrass.

In 2019, McIlroy began the Open with a 79 at Royal Portrush and furiously rallied the following day but came up short of making the cut.

“That’s all I can focus on,’’ he said.

DeChambeau was more optimistic. After his poor first nine, he calmed down, with a bogey at the 15th and an eagle at the 16th.

“I’m just proud of the way I persevered today,’’ DeChambeau said. “Shoot, man, I could have thrown in the towel after nine and could have been like, I’m going home. But no, I’ve got a chance tomorrow. I’m excited for the challenge. If I have some putts go in and hit some shots the way I know how to and figure out this equipment stuff, I’ll be good.’’

The Open has a 36-hole cut of 70 and ties.