You know, some people bet based on emotion. What I mean is that people bet on Barcelona because they are fans of Barcelona and do not just consider the performance. They don’t really have anything like fear in them when betting on Barcelona. If not for the way they turned out to be, I would also be surprised, and I expected Barcelona to perform more than they did. However, that is football.
Sometimes even if a team is the strongest in the competition, they won’t always be good; sometimes they mess up things. Vallecano players are very confident in the match; they came ready because they know how strong and good the Barcelona squad is this season, so they came prepared.
Every team against Barcelona tries to show their best performance, and they also try to defend very well because they know that Barcelona is an attacking team and will create a lot of chances. Rayo Vallecano were lucky to play well in defense and, moreover, they were lucky to score a goal. Yes, you are right that sometimes such matches happen, and Barcelona expected to get an easy win here, but afterwards they couldn’t pull themselves together and score again. It’s disappointing to drop points at the very start of the league, but that happens too.
Dropping points like this is now considered normal in the long-running Spanish league, as it's one of the toughest leagues in the world. Even Barcelona can drop points in such matches. They've fallen behind Real Madrid, but that's not a problem because they faced similar difficulties last year, but Barcelona won the championship at the end of the year. If they can maintain a similar dominance in their matches against Real Madrid as they did last year, they could overtake them. However, Real Madrid isn't the Real Madrid they were last year; they appear to be more organized and have a stronger defense. Barcelona could also drop points against them.