I think it will be really amazing if Real Madrid can win this match against Chelsea. because almost everything points to Chelsea's win in my opinion and the only thing that is probably in Real Madrid's favor is their ability to play great football in the Champions League. Other than that I think in almost every other aspect Chelsea is better than Real Madrid.
For this match, the chances of both teams to win are 50:50. if in the 1st leg Chelsea can beat Madrid out then their chances in the 2nd leg to win are also bigger, Benzema must be able to play from the start of the match, if don't want to see madrid lose badly to chelsea.