Why not? If you pay top bucks for an experienced international and PL player why is it so hard to expect him to play a vital role in the big matches? Or atleast start in them. I seriously doubt SAF bought him with a view to being an 'option' player, something that he became at United. In that sense he has underachieved. Fergie clearly paid the fee because he felt Berba could be the man who would unlock defenses in big matches. Berba isn't a flop. But I don't think he's become the player he was brought here for. He isn't an outstanding success either.