Tom Mohan's side were made to rue a disallowed goal as they suffered a narrow friendly defeat against Slovakia ahead of Uefa Championships qualifying
A 77th minute penalty was enough to see off Tom Mohan's side as the Boys in Green struggled to come out on top in a tight encounter.
Danny Kane almost put Ireland ahead early into the game when he stuck the post after getting onto the end of a free kick on 10 minutes. Najprv Kondrlik hit the post for Slovakia soon afterwards in a frantic start to the game.
Ireland had a goal disallowed in the 73rd minute when Tom Holland was adjudged to have been offside and they were punished minutes later as Adrian Kopicar stepped up to blast a penalty past Evan Moran.
"We were unfortunate," Mohan said after the game. "We'd some great chances to go 1-0 up then conceded a very soft penalty. It was a much improved performances and we'll take a lot from it.
"We had a couple of very good chances and in international football you have to take those chances. The players worked hard and you couldn't fault anybody. They showed character to get on the ball.
"I was disappointed for the lads but it's about us getting to know the players and for them to see how we work.
"It would have been nice to win it but the most important thing was to learn as much as we can ahead of the UEFA Championships qualifying tournament in October."
Ireland will travel to Armenia next month where they will meet Gibraltar on October 24, the Armenians on October 26 and England on October 29.