Paul Dunne began his Open campaign with a level par round of 71 at Carnoustie.
The Wicklow man, who famously held the joint lead ahead of the final round as an amateur in 2015, opened with a bogey but quickly evened that out with a birdie on the second.
Another dropped shot followed on the ninth but a birdie on the 12 got the Greystones player back to even.
Shane Lowry was also among the early starters in Scotland but the Offaly man never got going.
The front nine consisted of two bogeys and one birdie and a double bogey on the tenth ensured he will face an uphill battle to make the cut tomorrow.
"From 104 yards out, to take a double bogey was a kick in the you-know-whats," Lowry, quoted in the Irish Examiner, said.
"In a tournament like this, you do that and you can't compete.
"I fought hard to get up and down on 15, 16 and to make par with two putts from 40 yards on 17. But I made mistakes and you can't do that."
Darren Clarke, the 2011 champion, endured a miserable round that included four double bogeys, five bogeys and two birdies.
The Dungannon man signed for an 11-over-par 82.
Rory McIlroy, the 2014 champion, is three off the lead while 2007 and 2008 winner Padraig Harrington faces a battle to make the cut after posting a nightmare five over par.
