Rory McIlroy conceded he did not adapt to the difficult conditions at Royal Troon as he carded a dismal first round at The Open. (More Sports News)
McIlroy's hopes of clinching his first major title in a decade took an early blow as he went round in a seven-over par 78 on Thursday.
The Northern Irishman came agonisingly close to winning a fifth major title at the U.S. Open last month, only to wobble on the final holes.
And while McIlroy took time away from the game to re-focus, he could never get going on day one in Scotland, and in windy conditions, sliced a shot on the 11th so far into the rough, that spectators had to help look for the lost ball.
"Yeah, a difficult day," McIlroy said.
"I felt like I did OK for the first part of the round and then missed the green at the Postage Stamp there and left it in [the bunker] and made a double.
"But still, I 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.
"You have a strategy that you think is going to help you, but when you get a wind you haven't played in, you start to think about hitting a few clubs that you haven't hit in practice. I just didn't adapt well enough to the conditions.
"Your misses get punished a lot more this week than last week [at the Scottish Open] or even any week, whether you miss it in a fairway bunker or even the rough. The rough... the balls that I hit in the rough today, the lies were pretty nasty."
McIlroy was not the only big-hitter to struggle on day one, with Bryson DeChambeau – who edged out McIlroy at Pinehurst – also floundered, carding five over.
"I could have thrown in the towel after nine and been like, I'm going home," he said. "It's a difficult test, something I'm not familiar with. I can do it when it's warm and not windy."
Shane Lowry (five under), Justin Thomas (three under) and Xander Schauffle (two under), however, all enjoyed much more fruitful rounds.
Meanwhile, Daniel Brown emerged as the surprise overnight leader. The Englishman carded a bogey-free 65, including six birdies, to take a one-shot lead into day two.