Republic of Ireland endured a painful reintroduction to life among the elite as mistakes costs them dearly and they fell to a 3-1 defeat in their European Championship opener against Croatia.

The Republic's first major tournament for a decade and first Euro finals since 1988 may prove a bridge too far as two goals from Mario Mandzukic and one from Nikica Jelavic put their opponents in control of Euro 2012 Group C and left them with a mountain to climb.

Sean St Ledger's header had earlier cancelled out Mandzukic's opener but goalkeeping and defensive errors ultimately proved Ireland's undoing as their 14-match unbeaten run was ended in Poznan.

Croatia started much the better and received their reward when captain Darijo Srna's right-wing cross clipped full-back Stephen Ward and sat up for Mandzukic. The striker had slipped as Srna prepared to deliver, but managed to right himself and head into the bottom corner.

The combative Kevin Doyle was giving Vedran Corluka a torrid time and forced the Tottenham defender to concede one of a series of free-kicks. Aiden McGeady's delivery to the far post was firm and true and with Corluka out of position, St Ledger crept in front of him to head Ireland level from close range.

Goalkeeper Shay Given dispelled any fears of his health with a fine diving save from Ivan Perisic's firmly-struck 22nd-minute shot, and he was grateful to see the same man thump a dipping volley wide nine minutes before the break.

Ireland looked to be heading in at the break all square until disaster struck with two minutes of the half remaining. The increasingly influential Luka Modric cut inside the covering Robbie Keane to fire in a long-range shot which was blocked, but in his haste to clear, Ward could only slice the loose ball to the delighted Jelavic, who easily beat Given from close range.

Given's luck deserted him totally within three minutes of the restart when Mandzukic powered a header towards goal from a Perisic cross and saw the ball come back off the post, hit the keeper on the head and fly into the unguarded net.

The Irish were convinced they should have been awarded a 63rd-minute penalty for central defender Gordon Schildenfeld's crude challenge from behind on Keane, although Dutch referee Bjorn Kuipers took a markedly different view.

Midfielder Ivan Rakitic curled a 77th-minute shot inches wide and Keith Andrews power a header agonisingly past the post at the death, but the points had been secured long before.