It will be a tough game. Don't think that Barca will be any more "fine" than they were against Bilbao.
Could be a good contest, but let's take a look at tactics.
There are only two ways anyone has been able to beat Barça: 1) press like crazy all game with young fast legs, or 2) bunker down, hit on the counterattack, and win set pieces.
Bilbao pressed like a pack of crazed meth addicts and eked out a 1-0 result at home. Ajax youth edged 2-1 in a meaningless game (also missing Messi, Valdes, Alba, Alves, and Adriano).
So what's City going to do? They aren't going to press (Toure would be carried of the field on a stretcher after 15 minutes), so are they going to bunker down a la Mourinho Real Madrid and try to hit on the counter? Are they good enough to beat Barça in open play leaving space between the lines?