The Italian replaced the new Republic of Ireland manager at the Stadium of Light towards the end of last term and immediately criticised his inherited squad for being unfit, before helping them survive in the Premier League.
However, Di Canio's reign was brought to an end after just 13 games following a poor start to the current campaign, and O'Neill could not hide his satisfaction at the result following the former Swindon Town manager's earlier outburst.
"Paolo Di Canio? That managerial charlatan," O'Neill responded when asked about his successor in a press conference. "Paolo stepped in there and basically, as the weeks ran on, he ran out of excuses. I had a wry smile to myself.
"It was like a 27-year-old manager stepping in and the first thing you do is criticise the fitness of the team. If you've ever seen Aston Villa play, you'll see the one thing I pride myself on is teams being fit.
"I'd have loved to have the opportunity to sign about 15 players like Paolo did, I never got that opportunity. I think, really, although nothing is certain in football, that, given 20 years of reasonable success in the game, I would have accumulated the five points necessary from the last seven games to have stayed up. So yes, I was disappointed, because it was a club that I grew up supporting as a boy."
O'Neill was confirmed as the new Ireland boss last week.