It's amazing how Barcelona have impressed even without Messi. Once upon a time, they'd be desperate for him to return. Indeed, they've only played two El Clasicos without him since 2007 I think, and lost them both. Neymar has really shone, though, and I fully expect them to beat Real.
I think Benitez's best hope is having Marcelo get down the left and have the beating of Dani Alves for the full 90. If that happens, they'll cause problems.