Sessegnon has admitted to Mourinho that he has a quiet personality on and off the pitch, something the Portuguese is looking to change.
"Really he just sat me down, told me to be myself, told me to be a bit more vocal because I am quite a quiet player and person in general," Sessegnon revealed.
"I think he wants me to show a bit more personality, show a bit more of me, show that I want to play, show that I will fight for my place in the team and a lot of strong words really.
"I'm still young myself but I'm someone who needs to be more vocal around the pitch, off the pitch and really want to stamp my ability on this game.
"I have to work hard to break through into this team and really show that I can do that. I think it's a fair point that he's made, to be honest."