Szczesny: When Barcelona are at their best, few teams can compete and the season is not always smooth sailing

. I would be critical of the way we perform in this system in certain games. There were two games this season where we didn't do well enough, one at Rayo Vallecano and the other at Sevilla, and it was a clear message that we have to do better. The system is not the problem, the problem is usually how you act within the system.