Agree. Real Madrid is the favorite team to qualify for the next stage (round). Chelsea seems very inconsistent to play, they will have no chance to beat Real Madrid. I believe Real Madrid will be more serious to play in UCL because they miss the chance to win La Liga title. Ancelotti and Real Madrid will focus on winning UCL title because it is the most prestigious title that they can achieve now.
We can't compare Real Madrid with Dortmund, they have a very different squad quality. Real Madrid has a stronger squad and they are more experienced in UCL matches. Real Madrid is well known as the most successful team in UCL, they always know how to give the best performance in this competition. Another factor is surely about the coach, Ancelotti is on another level if we compared with Chelsea coach (Potter).
In football anything can happen even now I'm not too brave to say that Chelsea will lose against Real Madrid. Even though Chelsea performance this season is not very good in the domestic league, they are showing their strength in the champions league. The first leg will be quite interesting to look forward to from this game because Chelsea will travel to the Bernabeu stadium in the first leg so there is a possibility that they will get a stronger obstacle to beat real madrid in front of their fans.
Real madrid is not an arbitrary opponent for every team that faces them because real madrid has quite complete perfection in the champions league, but one thing I doubt is that they have lost their best form recently in the domestic league whether this will affect them in Champions league.