Barcelona does control the field, because the style of play they apply will increase the percentage of possession. But in the champions league it is not ball possession that is desired in the field. Because some clubs that are included in the champions league will not serve that kind of style of play. They will continue to make breakthroughs with Shots for sure.
A good game is expected, it will be very entertaining but, you can't always win even if you play well. Other teams score and defend, they want to secure points, the goal is to win. In essence, Barcelona failed not because they played badly, but failed because their strategy was easily broken by a team that defended and counter-attacked well.
Back to the topic of LaLiga.
Barcelona have yet to meet Real Madrid as eternal rivals, and we will see El-Clasico drama. So we will see that as a determination of the performance that comes out as the winner this year.
No drama, Real Madrid are the favorites at home.