In fact, there is a big difference between Barcelona in the Champions League and La Liga. I think one of the reasons is that La Liga teams are relatively far behind Barcelona. Barcelona are beating them fearlessly. But Barca could not be ready for the Champions League yet. The upcoming match against Real Madrid will show how successful Barca is in La Liga.
If they finally get to win Real Madrid it'll mean a lot to Barca
Cause they have finally realized that they can't qualify to the next round in the Champions League
Playing Europa league has never been the option from the very beginning how painful it is to see Lewandoski in the Europa League Competition
Barcelona have been able to hold up ad even win there last El-classico with Real Madrid but that was in the La liga. I won't ay there performance is due to the fact that, they are way ahead of most of there competitions except for Real Madrid but, its mostly with the fact that, they see Real Madrid for a rivalry and as such, games with Real Madrid is always that personal.
The unfortunate situation for them is, this isn't Laliga, its the UCL and that's some league Real Madrid don't play around with. They are so experienced in the game and can always turn there worst day into history.
It would mean something if Barcelona could go personal on this but, its not going to he easy for sure. The best they might come up with would he a draw.