It's an intelligent analysis of Barcelona's tactics, by Alan Jacobs.
Barcelona doesn’t play a striker, and hasn’t since Ibrahimovic left. They just have a bunch of skilled players—you could call them midfielder-forward hybrids or something—who take turns orchestrating the attack and making runs to the goal. Normally it’s going to be Xavi who gets things going, but at any given point in the match the player launching the push forward could be Busquets, Alves, Messi, Iniesta, even Villa or Pedro (though in the last two cases usually from a wing). Seven different Barça players had shots on goal in the final; they finished with twelve shots on goal total. Meanwhile, only three Man Utd players took shots at all, and Rooney’s goal was the only shot on target. When you’re playing Barcelona, you just have no idea where the attacks are going to come from or who will be making them. How can you plan for that?