Don't take this the wrong way mate, but the fact you feel the way you do about the Champions League I reckon it's because you're not European. Maybe I'm wrong, but it's just that everyone I've ever known from outside the continent of Europe has always swayed that way.
That aside...
Anyone can beat anyone in a one off game and Real Madrid aren't perfect, much less THIS particular Real Madrid. Their feats over the past two years are misleading everyone to believe otherwise but results (aside from their disastrous domestic season) in Europe analysed properly also show us that it's more a game of nerves and mental excercises for rivals than what's really out there. Real Madrid are more vulnerable than over the past two years and this should be a major factor in anyone meeting them in what's remaining of the tournament. The issue is that the four remaining teams all have their issues from entity size to question marks on other factors which could mean it all equals itself out in the benefit of Madrid... Who knows, we'll see soon enough!
Another thing... I've mentioned it before!
Due to the size of Real Madrid, how they're run, how the entity (Florentino Pérez) runs the club, the direction that club is run... If they don't win the Champions League this season coupled with the disaster domestically on all fronts, they will be the total focus of everything in the hell hole that the Spanish sports media is. Infact no credence or media coverage will hit the eventual winners of the Champions League and the Barcelona press will also hit as hard as they can for the summer months which will seem eternal to the Madrid cavern... It could mean mayhem in that entity all the way from the bottom to the very top. Barça's season will all of a sudden become one of their greatest and Real Madrid will be in total tatters. That's the way it works in Spain.