Beretta criticised Mourinho for not attending an Inter media conference last week, but the Portuguese hit back prior to last night's derby defeat.
"Barnetta (sic) spoke to me at the stadium and didn't say anything. I may have an irritating face, but not one of a person who is mean or violent," snapped the Inter coach.
"Why didn't he say this to me in person? Maybe he needs to work a little more on his character if he doesn't know how to talk to colleagues and then sends them messages via the media.
The message filtered through to Lecce, where Beretta did not hesitate in giving his response to this personal attack from Mourinho.
"I have no character? Who can possibly say that? Nobody. I think the issue should end here, as I have more important things to think about than this stupid rubbish.
"I consider Mourinho a professional who is intelligent and never banal in his statements. My judgement won't change, just as my freedom to say what I want will not change.
"I replied to a question that was posed to me. If he wants to continue this argument, that's his problem."