Barcelona's performance against Inter Milan was incredible, although I understand some people were expecting them to win the match, and since they failed to win against Inter Milan, they are saying Barcelona performed poorly in that match. If not, your obvious Barcelona performance was very good; I think luck wasn’t on their side. If not, everyone knows their performance against Inter Milan was not bad.
Despite Barcelona's bad performance, but to me both Inter Milan and Barcelona performances were excellent, and the teams was quite powerful. Because, as you mentioned, their performance was outstanding, that is how it goes. They said that football is unpredictable because the outcome was not in their favor. Even if they stated that PSG will win the Champions League, I will not believe it and with efforts they make it possible.
Barcelona will do more than they did last season in the next coming season. I’m expecting Barcelona to top both the Champions League and La Liga competition. They are strengthening their squad currently to make sure things go well for them next season. They will continue from where they stopped last season, and we will see a better performance from Barcelona.
Football is a game where anything is possible. Barcelona is capable to do more than they did in the previous season. But It is possible that their performances will be less impressive in the upcoming season if they cannot able to maintain their high level of performance from the previous one.