Yaya Toure fired City into their first final since 1981, where they will play the winners of Sunday's clash between Bolton and Stoke.
Mancini's men will be strong favourites to claim their first trophy since the 1976 League Cup at Wembley next month but the Italian claimed the final would be even tougher than Saturday's 1-0 victory.
A delighted Mancini said: "I'm very happy. I'm very happy for our supporters.
"They deserve to have a day like this. We mustn't forget we play another game. But we have only won the semi-final."
Source: PA
Source: PA