For Chelsea this can be a dream to beat Real Madrid in this situation both teams, currently, we know Real Madrid is in a good situation after they won the El Clasico and had a perfect performance there against Barcelona while they had players like Benzema shining at this match, while Chslea just started working with Lampard and comparing to Ancelotti he doesn't have enough experience to win this game.
Exactly, Lampard also have an experience to manage Chelsea in the past, but his strategy isn't fit with players and board member decided to sacked him. I know with Chelsea, he only has a job till end of season, but waiting for this Madrid need to make sure all of players ready to playing all out for the chance playing in UCL semifinals. Ancelotti and Madrid on better conditions, I think for the first leg, Madrid will trying to playing defensive with counter attack.