"It's a very alien feeling," McIlroy said. "It's something I've never had to deal with before."
McIlroy seemed bewildered after a round of missed opportunities, missed putts and even a putt that went into a bunker. By the time he tapped in for a final bogey on the 18th hole and shook hands with playing partners Phil Mickelson and Hideki Matsuyama it was all he could do to add up the damage and sign his card.
A few days earlier, McIlroy was talking about how hopeful he was that he was finally ready to come out of a season-long slump. On this unusually warm day on the Scottish coast he sounded like he was searching desperately for something, anything really, that could save his game.
"I just need to try to think more," he said. "I'm trying to focus and trying to concentrate. But, yeah, I can't really fathom it at the minute and it's hard to stand up here and tell you guys what's really wrong."
It was just 11 months ago that the 24-year-old McIlroy won the PGA Championship for his second major championship win. Since then, he ditched the clubs that had served him well to sign a rich endorsement deal with Nike.
He put a new driver in the bag for the Open, hoping to straighten out a flaw that had him leaving his tee shots to the right. But that's just where he was on the 10th hole, deep in knee-high rough on his way to his first bogey on a back nine littered with big scores.
The swing, he insisted, was fine. But the mental errors added up quickly, with McIlroy making a double bogey on the 12th hole after short siding himself with a short iron and putting from just off the front of the green into a back bunker on No. 15 for another double bogey there.
"It's just so brain dead," he said. "Seriously, I feel like I've been walking around out there like that for the last couple of months. I'm trying to get out of it. I just don't quite know why."
McIlroy, who has yet to win this year and finished tied for 41st last month in the U.S. Open, was candid as he answered questions after his round in a steamy interview area off the 18th green. He stood with his hands in his pockets and talked about how things weren't all that bad before he began making mental errors on the back nine.
It's the first time in his career that he has struggled for so long, and McIlroy acknowledged it was difficult to deal with. But he rejected the notion that having big success at such an early age may have set him up for some failures now.
"I don't think so," he said. "All you're trying to do is get the ball in the hole in the least amount of shots as possible. That's all you're thinking about out there or trying to think about. And that's what I've been so good in the past, and obviously that's the point I'm trying to get back to."
If McIlroy needed any reminder of how far he has fallen it came when he was playing the back nine and his name appeared on a leaderboard just off the 15th hole.
It was a mistake, and quickly taken down.
