After a rocky road to Euro 2012 that saw them both forced to earn their berths via the playoffs, Ireland and Croatia will aim to make a solid start to their tournament when they meet here on Sunday.
Keenly aware that much attention will be focused on Group C favourites Spain and Italy who meet the same night in the Baltic port of Gdansk, both sides know that a victorious start is the key to their campaign.
"In any competition you want to start off as well as you can, and get points on the board," said Irish record goalscorer and captain Robbie Keane.
The match also throws up what should be a fascinating clash of the coaching generations.
For it pits Ireland's veteran 73-year-old Italian coach Giovanni Trappatoni - perhaps the most successful club coach of all time - against one of the brightest young coaches in 43-year-old Slaven Bilic.
Fans' expectations are high after Ireland beat minnows Estonia to reach their first European championship since 1988 and first major finals since the 2002 World Cup, helping overcome the trauma of falling controversially to France in the playoffs for the 2010 World Cup.
Boys in green are level-headed
"We know we're in a group where anybody can beat anybody so every point is crucial," said Keane, who along with goalkeeper Shay Given and forward Damien Duff shone at the 2002 World Cup where they went out on penalties to Spain in the second round.
"We've not set ourselves a target, we'll take each game as it comes, but we're focused on Sunday's game now - and hopefully after that we'll be talking about having three points in the bag."
They are clear about the battle lines in the group.
"For both teams, it's a massive game," said midfielder Keith Andrews.
"Spain are red-hot favourites to win the group and ourselves, Italy and Croatia are probably vying for second spot, if we're all being honest," he underlined.
Croatia, meanwhile, knocked out Turkey in the playoffs, exacting revenge for the Turks' penalties victory in the Euro 2008 quarter-finals.
After six years in charge, Bilic would like nothing better than to lift the trophy before he moves into club management with Russian side Lokomotiv Moscow.
Star midfielder Luka Modric reckons that the result against Ireland will be the key to Croatia's ensuing performance.
"It's our most important match in the group," said Modric.
"If we win it, then I believe we will reach the knockout phase."
Modric has just recovered from a bout of flu, but Croatia have been plagued by injury, losing midfielder Ivo Ilicevic, defender Dejan Lovren and veteran striker Ivica Olic.
Last Saturday, Croatia drew 1-1 against Euro 2012 non-qualifiers Norway in a friendly - while Ireland had a disappointing 0-0 draw on Monday against Hungary, who also failed to reach the tournament.
Bilic has said his optimism for the tournament is undampened, however, and that he is targeting three points from Sunday's game
Captain Darijo Srna echoed that.
"We will show our character and our real face in the match against Ireland," he said.
Ireland last played Croatia in an August 2011 friendly in Dublin which ended 0-0.
In total they have met five times, with two wins for the Irish, one for the Croats, and a trio of draws.
Ireland : Shay Given; John O'Shea, Sean St Ledger, Richard Dunne, Stephen Ward; Aiden McGeady, Glenn Whelan, Keith Andrews, Damien Duff; Kevin Doyle, Robbie Keane (capt).
Croatia : Stipe Pletikosa; Darijo Srna (capt), Vedran Corluka, Gordon Schildenfeld, Ivan Strinic; Ognjen Vukojevic, Ivan Rakitic, Luka Modric, Ivan Perisic; Nikica Jelavic, Mario Mandzukic.
Republic of Ireland V Croatia - view commentary, squad, and statictics of the game live.