Martin O'Neill has launched a stinging attack on Paolo Di Canio, the man who succeeded him at Sunderland, branding the Italian a "managerial charlatan".

Di Canio was appointed after O'Neill's sacking in March but lasted only 11 games before suffering the same fate. Di Canio was critical of O'Neill's tenure and, specifically, the fitness level of the players he inherited from the Northern Irishman.

O'Neill has now taken charge of the Republic of Ireland in a controversial partnership with Roy Keane. When asked if he was disappointed by comments made about his Sunderland regime by Di Canio, O'Neill replied: "Paolo Di Canio? That managerial charlatan – absolutely, yes.

"Paolo stepped in there and basically, as weeks ran on, he ran out of excuses. I had a wry smile to myself."

O'Neill clearly took particular exception to allegations that his players were not fit. The 61-year-old said: "It's like a 27-year-old manager stepping in and the first thing you do is criticise the fitness of the team beforehand. If you've ever seen Aston Villa play, you'll see the one thing I pride myself on is teams being fit.

"What you'll find interesting is that when he started the team wasn't fit for the Chelsea game. Then the following week when he won at Newcastle, not being fit wasn't mentioned.

"Then about two weeks later they got mauled by Aston Villa, someone asked him about the fitness. Suddenly, he didn't know where to go. Because the team, as it progresses, should be getting more fit.

"And then, at the start of the season, when he lost by a late goal at Southampton, he was asked about the fitness regime, that he was going to have them the fittest team in the league. Suddenly, the fitness wasn't for that game but for Christmas, when the winter months set in. You know, I did have a wry smile at that one."

O'Neill garnered similar amusement from Di Canio's decision to ban various foodstuffs. When in charge of Sunderland, Di Canio explained: "We need to have lectures about why we can't have every day things like mayonnaise, ketchup and Coke."

Speaking after he was officially introduced as Ireland's manager on Saturday afternoon, O'Neill said: "I'm hoping at some stage or another [Sunderland's captain] John O'Shea asks me at dinner table to pass him the tomato sauce and I will dispose of it immediately. But then if I feel you can't win games without tomato sauce I will empty it on his plate, with the chips.

"John Robertson [O'Neill's former assistant] once said that if every team in Italy has pre-match pasta for their meals, how come three get relegated each year? It's an interesting point. Ability might come into it. I'd have loved the opportunity to sign 15 players like Paolo did. I never got that opportunity.

"I was very disappointed at the outcome. I think I would have garnered the five points necessary to have stayed up and [had] the chance maybe to have changed the side."

The phone of Di Canio's agent Phil Spencer was ringing out yesterday.