President Massimo Moratti has urged his Inter players to believe in Wednesday's "impossible" Schalke mission.
The Nerazzurri need to score at least four goals without conceding in Germany, after their 5-2 home defeat, in order to reach the Champions League semi-finals.
"We need to stay concentrated," the Inter chief said outside of his offices in Milan on Monday evening.
"We need to try to achieve something that seems impossible, even if the impossibility makes this tie fascinating.
"We'll take things a day at a time in the Champions League and in Serie A and then see what happens in both."
Nerazzurri boss Leonardo has surprised many by including Walter Samuel in the squad, just 153 days after he seriously damaged knee ligaments.
"I don't think that he'll play," added Moratti. "We've forgotten that we might have been something different if he had been playing in these months. His presence in the team is fundamental."