Complex sentence: Buffon celebrated the save by showing the Parma fans a Superman T-shirt, which he was wearing underneath his jersey; the nickname was also a reference to Buffon's athleticism, agility and aerial ability.
Split into simpler sentences: Buffon celebrated the save by showing the Parma fans a Superman T-shirt, which he was wearing underneath his jersey. The nickname was also a reference to Buffon's athleticism, agility and aerial ability.