PORTRUSH, Northern Ireland — It was a tough day to be one of the stars of golf in Thursday’s first round of the British Open at Royal Portrush.

A bizarre day of stunning high scores posted by some of the world’s best players began with Rory McIlroy, the nation’s prodigal son and its greatest hope to hoist the Claret Jug late Sunday, taking a quadruple bogey on the first hole and finishing with a shocking 79.

It continued with Phil Mickelson posting a 5-over-par 76, then Adam Scott shooting 77, defending British Open champion Francesco Molinari and reigning U.S. Open champion Gary Woodland each shooting 74 and then hometown favorite Graeme McDowell turning a subpar round into a 2-over 73 with a triple on the last.

The day ended with Tiger Woods, the reigning Masters champion and No. 5 ranked player in the world, stumbling to a 7-over 78. It was Woods’ second-highest round in a British Open after the 81 he shot in torrential rain and winds in the 2002 at Muirfield.

Amidst all of the stars who faded on this day were some stellar rounds, led by leader J.B. Holmes, who shot a 5-under 66. Shane Lowry is a shot back entering Friday’s second round.

Fourteen players — including Brooks Koepka, Jon Rahm, Sergio Garcia, Tommy Fleetwood, Lee Westwood, Tony Finau, Alex Noren and Webb Simpson — are 3-under and just two shots back,

In all, there are 16 players within two shots of Holmes’ lead, 19 players within three shots and 41 within four shots.

No player is lamenting his opening round more than McIlroy, who entered the week with such high hopes.

McIlroy began his round by tugging his very first shot out of bounds to the left of the first fairway and taking an eight on the par-4 opener. To McIlroy’s credit, after a bogey on No. 3 left him at 5-over through three holes, he fought valiantly from there and played the next 12 holes in 2-under.

That had McIlroy at 3-over entering the 16th hole and in position to stay in contention.

But on the 16th, a par-3, he three-putted from 6 feet, including a 1-foot miss on a tap-in for bogey and took a crushing double that undid all the work he’d done to come back.

Then on 18, he cemented his fate with a triple bogey to close and leave him 8-over and a long shot to merely make the cut.

“It was obviously a disappointing day,’’ McIlroy said. “I didn’t put it in the fairway enough to play. You need to put the ball in the fairway here if you want to do well. I didn’t do that enough today to create enough scoring opportunities.’’

McIlroy said the implosion on the first hole “almost settled me down.’’

“It was almost like, ‘Well, that’s sort of the worst that can happen. Put your head down and keep going,’ ’’ he said. “At that point … what else can go wrong?’’

As it turned out, quite a bit more.

When asked if “there is a way back from 79,’’ McIlroy joked, “There’s definitely a way back to Florida,’’ referring to his home, which is where he’ll be headed if he misses the cut.

“Look, I definitely think if I can put the ball in the fairway [Friday] I can shoot a good enough score to be around for the weekend,’’ he said. “Obviously, I’m pretty sure anyone starting with a 79 in this golf tournament doesn’t think about winning at this point.’’

McIlroy insisted that this performance in a place so close to his home, 60 miles to the north, and such a part of his life as a youngster, doesn’t make Thursday hurt any more.

“I’d be disappointed regardless, whether it was here or St. Andrews or Birkdale or any of the other tournaments or majors,’’ he said. “So, yeah, I’m disappointed, but at the end of the day I’m still the same person. I’m going to go back and see my family, see my friends, and hopefully they don’t think any less of me after a performance like that today. And I’ll dust myself off and come back out tomorrow and try to do better.’’

He, too, insisted that the heavy weight of the expectations on him had nothing to do with his performance.

“I don’t think so,’’ he said. “I’m pretty truthful with you guys. Look, I was nervous on the first tee, but not nervous because of that. Nervous because it’s an Open Championship. I usually get nervous on the first tee anyway, regardless of where it is. So maybe a little more so today than other places.’’