Cesar's red came days after Nicolas Burdisso was sent off after eight minutes in the 2-2 Coppa Italia quarter-final against Juventus and Mancini snapped: "For the second leg against Juve next week we'll just step on to the field with 10 men, that'll resolve the problem.
"Considering the way the game was going, we risked losing it. Instead the lads did very well and I complimented them in the locker room.
"It was an extraordinary performance because we played a man down against an opponent of great quality and in good form. Despite it all we stuck together, created many chances and didn't concede much."
The Nerazzurri are refusing to talk to the media in protest at what Mancini claims is "prejudice" against the club, so all comments have only been released to Inter Channel.
Cesar also spoke to the official club network after he saw red for two bookings in the space of 30 seconds.
"The first yellow card was for my first foul, but that is understandable as we were in midfield and they were trying to counter as we lost the ball," explained the Brazilian.
"On the second booking I clearly went for the ball, but the player moved towards me. The referee was a little undecided, he was walking towards me and then talking to the linesman.
"It's true, I could have waited a little longer before going in for the tackle, but I went for the ball and not to hurt anyone."