I just watched the highlights and the commentator was saying there was a handball. I didn’t notice it myself. But Barca should never complain about the ref because there seemed to be handball ( penalty) on Ineista in the first half. Also there was a push by Barca defender a minute before the penalty which could have been called. Additionally in my opinion the free kick which Messi scores from didn’t seem a foul in the first place as it was messi who stepped on the defender’s foot.
So in conclusion, big teams such as Barca, Real, Bayern... should never complain about refs because 90% of the time calls go their way against weaker teams.