Italy's hopes of success at the World Cup depend on Mario Balotelli remaining completely committed on the field, Cesare Prandelli says.
Balotelli scored the winning goal as the Azzurri beat England 2-1 in Manaus on Saturday - a result which puts them in a great position to reach the knockout stages.
The AC Milan striker's contribution silenced many who had argued for him to be dropped in favour of Serie A top scorer Ciro Immobile prior to the match, but Prandelli insists his star man has to maintain his level.
"There are times when he was the asset and the weapon of this team, and it looked like he was take us to the moon," the coach told reporters.
"Then two months later he wasn't performing and some people weren't even sure if he would go to the World Cup.
"What really matters is that he concentrates and does what he did in the last match. We have 23 men and Mario is one of them. As in the last match, he must give 100 per cent."
Juventus duo Gianluigi Buffon and Andrea Barzagli remain fitness doubts having missed the England game and Prandelli admitted he still does not know whether either will feature against Costa Rica on Friday.
"It's an hour by hour process. We need to understand if their problems have been overcome. Barzagli had a minor problem, today he is fine. We can't plan too far in advance. We'll see.
"The same applies to Buffon. He has been excellent in the last three days in training. There is still swelling but not much. We'll see the reaction [on Thursday]."