I have said in the previous post, Flick's decision is very risky and he already knows the end result with that decision. considering the situation, there are not many options for Flick, with many injured players, a tight schedule, he took a risk with his choice. the worst is his defense, I'm sure Flick will find a way to overcome it.
It's a bad match with some bad decisions from Flick but losing a match is not losing a battle and Flick can win La Liga with Barcelona if they can play better in future. The season is very long and opportunities to win a title is opened for every strong clubs in La Liga.
Sometimes alternative players perform well but they can play terrible in other matches too. Barcelona received good compliments for their strong defense in previous matches, but this defeat changed many things and shown that Barcelona's defense system is not perfect and can be exploited too.