Rui Costa has urged Portuguese supporters to get behind Cristiano Ronaldo during tonight's Euro 2012 qualifier against Bosnia and Herzegovina.

Ronaldo has come in for criticism from a number of fans who have claimed that the Read Madrid attacker doesn't give his all while on international duty.

However, former Portugal international Costa believes that Ronaldo will do all he can to help his nation qualify for the tournament.

"No-one will want to make the difference in Tuesday's game more than Cristiano Ronaldo," Rui Costa told reporters. "To be criticised by other teams is a sign of his importance.

"What cannot happen is him being criticised by our fans and our country. He is one of the best players in the world, he is the captain of the team and we have to be proud to have him with us.

"We cannot think he will have to decide the match alone, but that he will do everything to make Portugal qualify for the Euro 2012 finals."

Ronaldo has made 86 appearances for Portugal.