I don't understand y everyone here is bashing Cassillas, i think he did good, Pirlo's shot was impossible to save, he didn’t had much choice then to attack Pato twice, he was always in front of Real's defenders & I think they're the ones to blame.
However Dida made a stupid mistake that costed Milan a goal.
Check the goals again: http://www.youtube.com/watch?v=LX9Qm_Yv9K8