Kaka impressed in the 2-1 triumph.
"The result of the tie is deserved and going through gives us confidence to get the tenth title. We knew the importance of the match, like we did against Barcelona.
"We have not won anything yet but it is a step forward. I am happy with the team because I know how hard it is to play here and to knockout Manchester United. I'm happy that we managed it. In football you never know what will happen and we still have a chance to win a double."