Di Canio made his feelings felt in a television interview on Friday, accusing O’Neill of being the charlatan and decrying his transfer dealings.
Martin O’Neill: “At the end of the day, it’s hardly worth it.
“You would have to go and check, but I don’t think Sunderland would concur with his £40million for a start. Even Sunderland wouldn’t do that.
“Seriously, one of those people he’s talking about (Steven Fletcher) actually, his goals helped Sunderland stay in the league, and Mignolet, they got £10million for.
“I think they owe a debt of gratitude to (Ireland goalkeeping coach) old Seamus McDonagh, McDonagh who I think Simon Mignolet - who is playing brilliantly for Liverpool - would say he had a major influence in his career development.”