It's a really difficult call and one i'm glad I don't have to make. It will be a big test of Pellegrini's balls I think, it must be extremely tempting to play Garcia in that hole and tell him to man mark Messi. The thought of us playing Ferna and Yaya and Messi dropping into that inevitable gaping hole, turning, then sprinting at our defence the way he does is pretty terrifying. If we can null that threat (easier said) we must have a fantastic chance, home and away.
If we do go with two in midfield, Vinny's performance will be vital. He likes to follow his man when he drops and hit him on his first touch. He will need to do that to Messi for nigh on 90 minutes.
It's a mouthwatering prospect that really could go either way. Whilst I agree with Neville to some extent, it is Messi we are talking about.