And the World Cup winner has recalled when Costa pushed Conte to make a tactical substitution as the funniest moment.
"When Conte first came to Chelsea I didn't really play the first three months. He made it clear he wanted a different type of midfielder," he told BBC Sport. "Nemanja Matic was playing, I had an injury as well and I didn't really play the whole season.
"Then we went to Manchester City, we had won seven games and Conte says to me: 'You have to play.' We won 3-1, I played well and gave the assist to Costa for 1-1. It felt like I had made a point to the coach that he could count on me.
"Next we played West Brom, Matic recovers and he starts. It was a typical game and for 70 minutes it was 0-0. They were defending well. The game was calling for someone like me to come on to open the door or do something but the minutes went by and nothing. I remember Costa coming to the touchline and shouting at Conte, saying: 'Put Cesc on!'
"Conte is not the manager you mess with this and he was pretending not to listen to Costa. Two minutes later he says 'Cesc come', and two minutes after I come on and I provided the assist for Costa to score."