Carvalho told the Daily Mirror: “I know Benni very well. He is a devil in the penalty area – very dangerous for defenders.
“I am convinced he will cause us many problems on Sunday.
“Blackburn are not all about McCarthy. They are a compact team. But for a defender like me, stopping McCarthy will be the key to victory.
“Cup semi-finals are often close matches. The chances are 50/50 and we must concentrate from the first minute. Blackburn are a hard team and in the Cup they have played at a high level. The match will not be easy for us.
“I have had a wonderful week in the Champions League but reaching the FA Cup final would make it perfect for me.
“I am always optimistic. Our dream is to win every trophy and we want to keep that alive.
“Against Valencia we showed we are ready for success, that we have the self-belief.”