Imagine a perfectly timed run from the far side. Ozil slips Benzema in, which is followed by a cool finish to the far post. But there's something wrong; the assistant referee has raised his flag and the goal doesn't stand.

Two Clásicos in two weeks. It's the Copa del Rey, sure, but it's still a Clásico. Will Barcelona outclass Real Madrid? Well, much of that argument will depend on the performance of Xavi, Barça's metronome in the midfield, and the club's continued mastery of Tiki-Taka football.