I don't think there is any serous teams overlook strength of their opponents. Whenever you see a team that is doing well broke down because a small team or a team that has been struggling in relegation suddenly outshine, it can only mean one thing and that's because the minor team took an opportunity and use it, they saw some flaws in the opponents team and executed it or rather they tried it and it work for them, this is why Barcelona draw their last game.

However, that doesn't mean Barcelona looks dull or they don't know where the problems came. Their last game goal they had, I still feel like they cheated their way to have that penalty, the replay shows that Yamal wasn't pushed, it was after the ball left his leg they both collide with the defender but they were quick to blow the game. I see it as a mistake that is if the referee that officiated the game didn't know, the Var could have done better to help him out.