Eusebio Di Francesco said referee Nicola Rizzoli “lacked courage” after revoking a Sassuolo penalty.
The incident occurred in the first half of a 2-0 home defeat to Roma,  when he at first awarded a spot-kick on advice from his goal-line assistant, then changed his mind.
“Rizzoli didn’t have the courage to take on the responsibility of awarding a valid penalty,” the Coach told Sky Sport Italia.
“These are incidents that can change the course of a season. I will not accept losing in this manner. Each person in football has to take their share of the responsibility.
“As for the game itself, it was a good overall performance, though we have to cut out these individual errors.
“We played on a par with Roma, a side who have triple our points in the table. We were good, but naive.”