Pep Guardiola has warned his side they must be at their best if they want to progress from the Champions League semi-finals.
Kevin de Bruyne, Gabriel Jesus, Phil Foden and Bernardo Silva were all on the scoresheet for City but a Karim Benzema brace and Vinicius Junior means it will be a tense affair in the Spanish capital.
Last season, City lost the Champions League final 1-0 to fellow English side Chelsea. The club are yet to win Europe's elite competition despite the Sheikh Mansour pumping billions into City.
Ahead of the last four encounter, Guardiola said he was confident in the ability of his squad.
"Yes, probably we will have to be better (than in leg one to go through).
"But at the same time I would like to tell you one thing - we could play much, much worse than we played and we could win, and not anyone can deny my assessment is right.
"So nobody knows, football is unpredictable. Sometimes you get something you don't deserve, sometimes you don't get something maybe you deserve, for the effort, for many things."
"We are two good teams. We saw it a week ago when we played. They are champions of Spain. We are trying to be champions," the City boss added.
"Both teams are good. I said a week ago we want to win and try and be in another final, for the second year in a row.
"(But there is) no guarantee the same guys will play the same way. I don't know what will happen tomorrow. We will try and win the game with the best XI possible."