He said: "Inzaghi could well be decisive once again. The team is in good shape and we are in the ideal condition to take on this very difficult and important derby.
A win would mathematically secure the Scudetto for Inter, but Ancelotti feels a Champions League spot is more of a motivator in this situation.
"The target up for grabs is very important for us, as we want to enter the Champions League and have another go at a competition that has given us a great deal. Perhaps for Inter there is not that sense of urgency, as they have another two rounds to get the points they need."
Ancelotti also had words of support for Ronaldo over his extortion scandal in Brazil.
He said: "I care about him and it's a shame. Certainly it wasn't his finest hour, but I am not going to judge people's private lives."