Rory McIlroy at US Open 2015: Thursday Leaderboard Score and Twitter Reaction

For much of Thursday, Rory McIlroy appeared to be playing patient, consistent golf—a strategy that makes sense at the always-grueling U.S. Open. But the hazardous course at Chambers Bay, University Place, Washington, eventually took its toll, and McIlroy finished with a disappointing two-over 72. 

It was McIlroy's putter that betrayed him on the day.

"I'm a little bit disappointed not to have shot a better score," he said after his round, via Fox Sports 1's television coverage. "I hit the driver well and gave myself plenty of chances from the fairway, it was just my putting today. I need to putt better going forward."

Ewan Murray of the Guardian, however, sympathized with his struggles on the day:

Nonetheless, it was that putting left him a bit buried on the leaderboard after his opening round.

As Justin Ray of the Golf Channel noted, McIlroy faces quite a deficit in the next three days that not many players have proven capable of overcoming at this tournament in recent years:

He'll also be battling his own personal history, per Ray:

As Chris Fallica of ESPN noted, the U.S. Open has been kind to McIlroy in recent years:

McIlroy, who opened on the back nine, got off to a nice start with a birdie on No. 11. That was quickly erased with bogeys on Nos. 14 and 15, before the world No. 1 quickly recovered with a birdie on No. 16. From there, McIlroy was the model of consistency, shooting to par over the next eight holes. 

It looked as though he would break that par streak at No. 5 with an eight-foot shot for birdie, but he sent it just past the hole.

He ran into trouble on No. 7, however, bogeying the hole to go one-over. He nearly recovered with a birdie on No. 8, but his putt from 10 feet was an inch short of reaching the hole.

His putting continued to fail him on No. 9, as he had a short putt to save par but failed to convert. For McIlroy, who had his struggles but seemed as though he was going to limit the damage throughout the day, finishing two-over was justifiably disappointing.

His stats on the day, in general, were fairly mediocre. Per PGATour.com, he had a driving accuracy of 71.4 percent, hit 12 of the 18 greens in regulation and had a rough 1.917 putts per greens in regulation. On a day when the weather conditions were pretty favorable, McIlroy missed an opportunity to score much better. 

Can he recover?

Ross Kinnaird/Getty Images

Well, probably. He's the world No. 1 for a reason, and if McIlroy improves his putting over the next three days, he should see his scores improve dramatically. Really, he easily could have finished the day under par if a few more close putts had rolled his way. 

Regardless, he certainly has his work cut out for him. He'll be hoping that the unforgiving course takes its toll on the top of the leaderboard in the next few days. If it doesn't, McIlroy will need to be nearly perfect to get back into the running. 

As it is, his margin for error is pretty low after Thursday.