For El Clasico, it will still be very interesting.
Barcelona's loss to Arsenal won't prove that they're bad because it's basically just a trial and see what players they bring in. It's just to try out some players so that they can adapt more and Xavi wants to see if there's potential from young players or not.
But when it comes to El Clasico even though it's just a friendly I think the result will be different. There's prestige to be maintained and even though it's a friendly I'm sure they'll go all out and a win will be sought even though they won't say it.
However, El Clasico is still El Clasico and they don't want to lose easily to a rival club.
When it comes to El classico, it's a different ball game. Although there might be too much intensity as a competitive match, but it would definitely be more than a normal friendly.
There's this bragging right that comes with the classico. They never want to lose to each other, no matter the circumstances. The rivalry is so strong that neither of these teams ever settles for a draw.
People say the rivalry of these teams have cooled down because Messi and Ronaldo no longer play for them but that's not true. The rivalry is always as strong as ever. That is why I laugh it off when I see people say "Madrid were not interested in the league last season". That's bullshit. If you follow La Liga you'll know how competitive they both are so there is no way they won't be serious for a competition like the Spanish league.
I'm looking forward to the El classico. I know it would be interesting, but I hope no player gets injured before the seasons even starts.