With Spain and Italy backed to advance from their pool, the Boys in Green and the 2008 quarterfinalists will be hoping for a victory in Poznan to set them on the right track.
O'Shea, Dunne, St Ledger, Ward
Duff, Whelan, Andrews, McGeady
Corluka, Schildenfeld, Simunic, Strinic
Srna, Modric, Rakitic, Pranjic
Republic of Ireland should have two stalwarts back in the lineup for their first match at Euro 2012 in goalkeeper Shay Given and defender John O'Shea.
Given had been struggling with back and calf issues, but has returned to full training and is set to add to his 122 caps on Sunday. O'Shea proved his fitness in the recent 0-0 friendly draw with Hungary by playing the full 90 minutes.
Danien Duff and Aiden McGeady will look to add width to Ireland's attack from the wings, but youngster James McClean will also be hoping for some minutes after an impressive campaign with Sunderland.
However, coach Giovanni Trapattoni must decide whether to go with five midfielders or add a partner for veteran striker Robbie Keane up front.
Meanwhile, Croatia boss Slaven Bilic will have to do without the services of Bayern Munich striker Ivica Olic, who will miss the duration of the tournament with a thigh injury. His place in attack should be taken by the in-form Nikica Jelavic.
Additionally, Olympique Lyonnais center back Dejan Lovren and Hamburg midfielder Ivi Illicevic have also been ruled out of the finals due to injury problems.
Nonetheless, there was some good news for Bilic as defender Vedran Corluka passed a late fitness test and is expected to be in the starting XI, so captain Dario Srna should feature in midfield rather than at right back.
|DID YOU KNOW?|
- The Republic of Ireland has only qualified for the European Championship once before this year's edition, being eliminated from the group stages of Euro '88.
- Trapattoni's side scored 10 goals from set piece situations during qualifying, more than any other team involved.
- The Boys in Green are on a 14-match unbeaten streak, last suffering a loss in March 2011 to Uruguay.
- Keane, who scored seven goals in qualifying, is his country's all-time top scorer with 53 strikes to his name.
- Croatia has only beaten Ireland once in six attempts, losing twice and drawing the other three times.
- Coach Bilic will step down from his post after Euro 2012 to take the reins of Russian club Lokomtiv Moscow.
- Defender Josip Simunic needs five more caps to equal the team record of 100 set by the retired Dario Simic.
- Croatia is a threat in the air - scoring nine goals during the qualifying campaign, more than any other side.