SOUTHAMPTON, N.Y. -- Rory McIlroy tied his career-worst major round score to par with an 80 on the opening day of the 2018 U.S. Open at Shinnecock Hills on Thursday after coming in as one of the favorites to win the tournament. He's 10 over through 18 holes and was 11 back of the 1-under lead at the time he finished.

Somehow, it may have been worse in person than it looks on paper.

McIlroy started his day innocuously enough with a missed 8-foot birdie putt on the par-4 10th (his first hole). After that, he went bogey-bogey-double-double, and the 80 watch was on. He played better on his second nine and even made consecutive birdies at one point, but then he bogeyed two of his final three holes to hit the round number he's hit twice before at majors (more on that in a minute).

It's tough to do much at a second-shot course like Shinnecock when you miss 13-of-18 greens in regulation, and in case that idea was in doubt, McIlroy confirmed it with the way he struck the ball on Thursday. The par-4 13th hole was a microcosm of this. After popping a drive in the proper position, McIlroy had 127 yards into the hole. He mishit his approach, found the sand and made double. 

I watched him for a while during the first round. As was probably obvious to everyone who followed, his iron play was not crisp. It's not like it was iotas off, either. McIlroy wasn't even close to hitting a lot of the lines it seemed he was trying to hit.

McIlroy has previously shot 80 twice in major championship, both of them notorious rounds; those came at pars of 72. The first was in 2010 when he went 63-80 to start The Open at St. Andrews. The second came in 2011 when he shot 80 in the final round of a Masters he led by four after 54 holes. This one was not as cataclysmic as either of those two, but it certainly wasn't pretty. It was also his worst U.S. Open score by two strokes and his worst first-round score at a major by one.

McIlroy wasn't alone in his Thursday struggles. His featured group, which included Phil Mickelson and Jordan Spieth (12 majors between them all, by the way), shot a combined score of 25 over on a wind-whipped day on Long Island. Mickelson played his first round in 77 and was low man (!) in the group. Spieth played it as an 8-over 78.

As ugly as the entire day was -- and boy, was it ugly -- this trio combined for just five birdies to four doubles, a triple and 20 (!) bogeys. Somehow, it still wasn't that much worse than the scoring average of 76 on the day at the time they finished. In other words, Mickelson was just 1 over "par" for the course. 

None of them are really in the tournament, but Mickelson and Spieth aren't completely out of it, either. The course should only bake from here, but if they can right the ship with something hovering around even par or better on Friday (admittedly, that would be unexpected after what happened on Thursday), they should be in halfway decent shape for the weekend.

McIlroy, on the other hand, will need something strong on Friday if he doesn't want to miss his third straight U.S. Open cut and something borderline heroic to play his way back into the thick of the leaders. I thought coming in a windy, fast, tough course wouldn't fit him all that well, and for one day anyway, it didn't. 

U.S. Opens are nasty and difficult and not for the faint of heart. One shot, two shots, three shots can lead to absolute destruction for your week. McIlroy and Co. experienced that time and time again in Round 1 as they combined to hit just 25-of-54 greens on the day. That's no way to win a U.S. Open, and it's certainly not a way to win one at Shinnecock Hills.