Costa and Conte spent the 2016/2017 season together at Chelsea where the Brazilian-born Spanish striker scored 20 top flight goals under the Italian to win the Premier League title.
The pair’s relationship started developing cracks midway through that season when Costa expressed interest in accepting an offer from the Chinese Super League as Chelsea were mounting their title challenge.
Costa’s move ultimately failed to materialize and he remained to help Chelsea win the league but he received a text message from Conte at the end of the season that his services were no longer needed at Stamford Bridge.
Costa finally departed Chelsea for Atletico Madrid in September 2017 while Conte was sacked in the summer of 2018.
Despite acknowledging Conte as a good manager, Costa believes the current Inter Milan boss needs to improve his man-management skills.
'[Conte and I] had problems off the pitch, but I think he is a really good manager,' Costa told ESPN.
'I have no hard feelings towards Conte, but to be a top, top manager, he needs to change the human side of his management.
'He is very suspicious. At a team like, say, Real Madrid, he would never last a season.'
