Di Canio believes Antonio Conte is in big trouble this season.
The Blues started their title defence with a 3-2 defeat to Burnley at Stamford Bridge on Saturday afternoon as Gary Cahill and Cesc Fabregas were sent off on the day.
Antonio Conte has brought in four players – Willy Caballero, Antonio Rudiger, Tiemoue Bakayoko and Alvaro Morata, but hasn't been happy about their transfer business this summer.
However, Di Canio believes the former Juventus boss will have some problems this season due to the west London club's transfer activity.
“I know Antonio very well and he does this [say season will be his toughest] because he is very clever to handle communications," the former West Ham forward told Tuttosport ahead of Chelsea's clash with Burnley.
“But I think he is also aware that in Diego Costa he is losing that malice which is so necessary to unlock games and to prepare his opponent’s next mistake.
“Conte got Morata who was the best at Real Madrid in terms of goals scored per minutes but he lacks that cantankerous attitude which really helped Chelsea to the title last season.
“Obviously he will also miss Matic because he can adapt to whoever he plays with whereas Conte will need to wait before Bakayoko makes any substantial impact on the game.
“We have seen Chelsea looking totally ordinary in the Community Shield without Eden Hazard – to Chelsea, he is worth what Ronaldo and Messi are worth to Real Madrid and Barcelona.
“I hope to be proved wrong, but also considering that he will have to pick some teams ahead of Champions League games, I think Antonio will have some problems this season.”