If Tevez is not world class, I don't know what is.
Silva is definitely in the next level of player (below the Tevez, Fabregas, Vidic types) which imight include the likes of Nasri
What they do have though are a lot of guys in the level immediately below that (probably equivalent to our Sagna).
something like
level 1) Messi, Ronaldo, Xavi. (that's a full stop)
level 2) Iniesta, David Villa, Eto'o, Sneijder, Fabregas, Tevez, etc
level 3) Nasri, Silva, etc
level 4) Sagna, etc
(lol)