The Italian coach hopes his side make less mistakes in the cup final against their fierce rivals and feels they have to prevent the Blaugrana from dominating possession
Barca completed a league double over Real at the Bernabeu last month in an enthralling game that finished 4-3 in the Catalan club's favour.
A hat-trick from Lionel Messi sealed the points in a game which Real had twice led, but finished with 10 men after Sergio Ramos was sent off after conceding the first of two penalties for the Argentina star.
However, Ancelotti's side have the chance for revenge at the Mestalla on Wednesday as Real look to repeat their achievement of 2011 by overcoming arch rivals Barca to win the Copa and the coach is confident in his side's abilities.
"We played very well at the Bernabeu but we made some mistakes," he said. "We did well during 30 minutes; tomorrow we have 90.
"Barcelona had more ball possession in the last few matches. We have to stop them from doing that in order to win.
"We've worked to avoid the mistakes we made at the Bernabeu. We will try to play with our style and identity. We worked all year long to be able to do it tomorrow.
"There isn't a problem with motivating the players. The players have a lot of desire to win."