Napoli coach Walter Mazzarri is unhappy with Italy's match officials.
Mazzarri is convinced refs are intimidated in big games.
He said: "I am not biased against referees, but at the same time do not tell me they don't really suffer from psychological submission.
"In order to help referees improve, the designators should pay attention and ensure they apply the rules the same way regardless of which teams are on the field.
"Mistakes can happen, but the real problem is that when in doubt they always favour the more important club."