You are right,Roma will fight it very hard to win this match,I know Jose Morinho was so disappointed in their last outing,where Atalanta won them,but I think they will want to do everything possible to win this game.Normally Morinho loves a defensive pattern of football,so we'll be pretty fair if we say Roma are more solid defensively than Milan,but the game will be tough because Milan will not let Roma win them just like that,they must try everything possible to either win or draw too.
Roma's chance of winning is still there in this big match considering that Inter's condition is not good now and Inzaghi is now in almost the same position as Allegri who is unable to sit still because of the results he has achieved so far.
The defeat against Atalanta must be used as a reference for them to rise again now because with that they can become more confident.