Ireland’s European Championship dream quickly turned into a nightmare in Poznan on Sunday – only a miracle can save it now after a crushing 3-1 defeat to Croatia.

Giovanni Trapattoni’s side were second best for almost the entire punishing Group C opener in front of a sell-out crowd of 44,000, most of them Irish.

The Green Army took over the stadium but the Croatians owned the pitch as a disastrous start and end to the first-half proved so costly.

Ireland were a goal down after just three minutes when goalkeeper Shay Given was badly beaten by a Mario Mandzukic header.

The Irish fans went crazy when Sean St Ledger headed home an Aiden McGeady free-kick to equalise in the 19th minute.

Croatia always looked the more likely team to score however and fortune was on their side when the referee ignored a foul on Stephen Ward and a possible offside in the build-up to their second goal from Nikola Jelavic right on half-time.

Any chance of an Irish comeback disappeared when Mandzukic was given too much room by the defence to score his second three minutes after the break.

Captain Robbie Keane had legitimate shouts for a penalty ignored as the game and the night went away from the Irish on their first appearance at a major tournament in 10 years.

“I am gutted, particularly for the fans here tonight,” said LA Galaxy striker Keane afterwards.

“We’ve heard there were 20,000 Irish supporters inside the stadium and maybe half as many again outside it. They were incredible but we didn’t do the business for them.

“You saw the numbers they turned out in and I’m gutted for the fans that we didn’t get the result for them.

“The goals just before and after half-time were the killer blows for us and it was always going to be an uphill struggle after that.”

Ireland face World Cup winners and reigning European champions Spain in Gdansk on Thursday night before returning to Poznan for their final Group C fixture against Italy on Monday week.

Spain’s defence of the title began with a 1-1 draw against Italy on Sunday afternoon.

Substitute Di Natale opened the scoring for Italy in the second-half but Barcelona midfielder Fabregas grabbed a deserved equaliser for the Spanish.