The former Arsenal star feels the Catalans must give more on the pitch, and is desperate to move on from their recent defeats
The Catalans recorded a favourable 1-1 draw at the Santiago Bernabeu in the first leg of the semi-final tie against Madrid, but they were brushed aside in the return fixture, with two Cristiano Ronaldo goals and a Raphael Varane header meaning Jordi Alba's late goal was nothing more than a consolation.
"We have to learn from this defeat. We have to give more," Fabregas told reporters.
"We have to pick ourselves up, move forward and win on Saturday. The two most important titles are coming up and we have to move forward.
"The loss against Madrid has nothing to do with the one against Milan. They are two different competitions.
"I believe in this team. We’re a bit down but starting tomorrow we have to start working hard because we represent a very important institution."
Barcelona will have the opportunity to seek immediate revenge on los Blancos, when they travel to the Bernabeu in La Liga on Saturday.