I really believe in the second game Barcelona will be better especially in terms of goal productivity. They couldn't score a single goal in the match against Rayo Vallecano, but that doesn't mean they failed to create many chances. The strikers that Barcelona have this season are much better, but we are just waiting to see how dangerous their form really is.
In the second week of La Liga Barcelona will visit Real Sociedad, and statistically Real Sociedad is better than Rayo.
I think Real Sociedad will play more openly than defend against Barcelona. From head to head statistics Barcelona always win against Real Sociedad either at home or away.
I also feel confident, in the second match Barcelona will get a perfect win.
Real Madrid will of course have to be wary of them this season, but it looks like Barcelona will still need some time to see their new signings adapt well. Raphinha, Lewandowski and Dembele are a trio who will be in good form this season, but they haven't proved much especially in the first game of the season.
real madrid have a more solid squad than barcelona when viewed from their first match, carlo ancelotti didn't bring in many new players this season, they are quite confident with the depth of their squad, i'm sure carlo ancelotti is wary of barcelona.
however barcelona is a squad that has the potential to win the standings rankings, although currently bercelona have not shown their best performance.