Costa Rica's familiarity with warm weather will help them against Italy, according to midfielder Thiago Motta.
Given little chance to exit a difficult Group D at the FIFA World Cup, Costa Rica claimed a stunning 3-1 win against Uruguay last week.
Arsenal's Joel Campbell starred in the come-from-behind victory, scoring one goal and setting up another.
And that has Italy – and Motta – wary, both about their talent in the final third and the fact they are more accustomed to the conditions in Brazil.
"They are a good side, with good individual players up front," Motta told reporters on Thursday.
"They are also more used to these weather conditions than we are.
"We will have to give 100 per cent, maybe even more. We will treat it as a final."
Italy also started Group D with a win as Mario Balotelli's second-half header sealed a 2-1 triumph over England in Manaus.comments