Tevez flourished and played like the best player in the world under CarlosBianchi and Marcelo Bielsa shows you what a big difference a very best manager can make to a very best player.
In addition to the aforementioned Van Gaal, Robson and Hiddink, you also have the likes of Giovanni Trapattoni (Bayern), Dick Advocaat (Borussia Moenchengladbach), Cesar Menotti (Sampdoria), Luiz Felipe Scolari (Chelsea) and CarlosBianchi (Atletico Madrid).