The Brazilian midfielder acknowledged that the team were lazy in the first-half and that such an attitude must not be allowed to manifest itself again this season
Two goals from Angel Lafita and a penalty from Gabi condemned Jose Mourinho to his second successive home defeat of the league campaign just days before Madrid face Barcelona in the Champions League semi-final second-leg.
"I think that we were really lazy in the first-half and showed a lack of spirit. We were slack. It cannot happen again this season," Kaka told AS after the game.
“You can lose points but not with the attitude we showed in the first-half. No matter what happens, you have to change that, as we did in the second-half."
Kaka admitted that the 2-0 home defeat on Wednesday against Barcelona had affected the team but insisted that the nine-time European champions still believe in their chances of progressing to the final of the Champions League.
"We believe in the comeback in Europe and in the league. As long as it is not beyond us mathematically, Madrid cannot stop fighting. We can not go wrong the way we did today on Tuesday."