Shane Lowry confessed that frustration got the better of him as he slipped to a 72 that could have been a 68 at a sun-scorched Ballyliffin.
As Graeme McDowell rallied down the stretch and made three birdies in his last six holes to post an encouraging 71, Lowry was relieved just to make two eight footers on the last two greens and salvage a level par round.
He knows he let a great opportunity slip away to get close to the leaders and must come out with all guns blazing today.
Five shots off the pace, Lowry said: “I played four bad holes at the end and I got a bit frustrated out there and let it get to me a little bit.
"But that was a nice putt on the last. I would have been very disappointed to shoot over par.
“The scoring’s not hectic is it, so try and get out early in the morning and shoot a good score.”
Out in an immaculate two-under par, he was still two under with four holes to go but three-putted the 15th and then drove into heavy rough at the par-five 17th and did well to save par from eight feet.
He pushed his tee shot into more heavy rough at the 18th but after getting a free drop to avoid the grandstand, he overshot the green, advanced the ball just a few yards and did well to salvage a bogey from eight feet.
He said: "It’s very frustrating because I was holing a few putts for birdie and felt I was going along nicely.
"And then I threw in a three-putt at 15, which was disappointing because I got away with my tee shot and hit a good second shot.
“But look, it could be worse, it could be better obviously, but I’ll get another go tomorrow.”
McDowell mixed three birdies with five bogeys in his first ten holes before digging deep on the way home, picking up late birdies at the fourth, sixth and eighth for his 71.
He said: "It was a grinding performance. It was one of those days that could have got away, and was happy to keep it under control and post something sort of half-decent.
"I felt like I could put all the stuff, the frustrations of early in the week behind me pretty well.
"I feel if I can get the putter heated up, I can make a lot of putts on these greens."
Defending champion Jon Rahm shot a frustrating 74 with back to back double bogeys at the 18th to blame.
McDowell said: "He seemed really irritated with himself this morning, not really sure why.
"But he's such a talented player and I'd expect him to be back firing on all cylinders tomorrow.
"Maybe as defending champion you just put that extra pressure on yourself. That extra expectation level. He's such an impressive player.
"He's one of those guys who just gets irritated with himself and isn't destructive for anyone else."
Lowry ended the day tied for 44th with Simon Thornton and Ruaidhri McGee as Paul Dunne drove out of bounds at the second and made a “brain-dead” double bogey en route to a 73 that left him tied for 66th with Colm Moriarty, Cormac Sharvin, Gavin Moynihan and Paul McGinley on one-over.
Darren Clarke, playing in his last Irish Open before he becomes a senior golfer next month, started double bogey-birdie-double bogey from the first and signed for a 75 as Monkstown's Cian McNamara posted a 76.
Old Conna's Neil O'Briain, who was playing his fifth round of golf in six days after heading from Irish Open qualifying to Open Qualifying in the UK, shot a six over 78.
The Dubliner did not manage to get a practice round after arriving in Ballyliffin on Wednesday.