Busquets made the mistake for the goal, that is correct but everyone would have made it. Mascherano (if im not mistaking) jumped for the ball and was very close to getting it, but ended up a little bellow it. At that moment Busi though El Jefecito would clear the ball, so he turned towards the field, Masch didnt get the ball and it ended up hitting Busi in the shoulder blades and being deflected towards Falcao who wasnt correctly marked by Cesc. Im not blaming anyone for that goal, they all played their part. I fucking hate corners...