The Spain international, who arrived from Real Madrid, has made an instant impact and has scored six goals in the opening six league games for the West London side.
Azpilicueta said: “I think he has adapted really well to the team and the way we play. The desire to be a big part of the team is huge.
“He is getting the reward he wants. I am trying to help him on and off the pitch. He is scoring goals and that is the main thing for him.”