Luka Modric thinks Croatia's game with the Republic of Ireland is "their most important in the group" at Euro 2012.
Both countries qualified via the play-offs and are competing with Italy and world and European champions Spain for a spot in the knockout stage.
"If we win it, then I believe we will reach the next phase. I believe we will play at our best and defeat Ireland," the Tottenham midfielder said.
"I even think we could go all the way to the end and win the tournament."
Croatia reached the quarter-finals at Euro 2008 but lost on penalties to Turkey having taken the lead with just one minute of extra time remaining before conceding an equaliser.
Niko Kranjcar, who sealed a switch from Tottenham Hotspur to Dynamo Kiev this week, said his team had learnt their lesson from that disappointment.
"If a similar situation to the Turkey game comes around then that scenario is not going to repeat itself," he said.
"The reason we lost to Turkey was a lack of experience. Now we are at our peak and we are more experienced."