The Watford boss was full of praise for the veteran Italian tactician ahead of his side's pre-season friendly with Cork City at Turner's Cross
"The groups were very tough and to be fair to them, Ireland tried their best," Zola told the Irish Examiner. "It was difficult though and the other teams were at a different level."
He continued: "If you look at the teams in their groups, they were unbelievable. I don’t think Ireland deserve much criticism because their opponents were a level above them."
The former Chelsea striker stressed that Ireland reaching the group stages of the European Championships was in itself an achievement and underlined the experience and stature of Giovanni Trapattoni.
"They did well just to get there, that was a great achievement regardless of their results during the championships," he added. "I feel it would be unfair to criticise Trapattoni because I think he has done a great job for the team.
"Obviously it’s difficult to stop criticism when you’re a manager of any team but to criticise a man of Trapattoni’s experience and history is a little unfair on him when they did so well to qualify for the tournament," said Zola.
Gianfranco Zola's Watford play Cork City tonight July 24 at Turner's Cross in a pre-season friendly. Kick off 19.45 BST.