Napoli coach Walter Mazzarri apologised to fans after their Coppa Italia thrashing by Frosinone.
Napoli collapsed 4-0 at the Maradona on Tuesday night.
“Perhaps the first choice players are not accustomed to coming off the bench and absurdly we did better with the lads who don’t play as often. We need to reflect on that,” Mazzarri told Mediaset.
“I want to apologise to the fans, they tried until the end to give us a hand and they did not deserve that. I do not like the way we ended the match and we will reflect on it together tomorrow.
“It can happen that the defensive shape is a little wrong after changes and the second goal was an accidental back-pass, but even when you are 2-0 down, you still have to remember that you are Napoli. It is not acceptable to end a game like that.”
He added: “When the fans cheer us on to the end, even when 2-0 down with 10 minutes to go, a goal could open it all up again. Instead, we just lost our heads. Maybe it was making two big mistakes for the goals that got to us.
“It’s a pity, you can lose in football, but not 4-0. We looked like everyone was just doing their own thing. I hope this can be a lesson for the future, as from tomorrow we must all look each other in the eye and change gear.”