Former Open winner Padraig Harrington admitted it was not a good day for him after he carded a four-over par 75 in the opening round at Royal Portrush.
Speaking after his round Harrington said his performance did not leave him full of confidence for the rest of the week.
"I thought I would have been better today, so it doesn't fill me with much confidence," he said.
"I know I'm on the right track. Just today was not a good day. I had a nice start, but I didn't play well after five.
"It's going to take some time. My game is there, physically, but mentally needs a bit of work.
"The course is set up nicely, it was very playable. A couple of putts could have dropped in the middle of the round. There were a significant number of putts that didn't go in, and clearly I lost momentum when it gets tougher after that.
"So it was a combination of a few weak shots and a few poor putts that didn't drop."
Harrington was more positive about The Open's return to Royal Portrush after a gap of 68 years.
He said: "The course is great. Atmosphere is great. It's unbelievable to have an Open, but we've been saying that all week. And I'm sure we'll say that next week."