World number two Rory McIlroy has put his lacklustre start at The Open down to "mental errors".
The Northern Irishman struggled through his opening round, ending up with an eight-over-par score of 79.
"I feel like I got off to a decent start, made a couple of silly mental errors on the fourth and fifth, a good two on seven and had a chance to get back to even par on nine. The start of the back nine was not very good," Sky Sports News quotes him as saying.
"Going left of the pin on 12, when I had no right to be going anywhere near that pin, that's just thoughtless. It's just so braindead.
"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 has not secured victory at a Major since winning the DP World Tour Championship in Dubai last November.
