The Argentine has scored twice since joining from Juventus on loan until the end of the season. And he hopes to continue firing in goals over the next three months.
He said in the club's official magazine: "I'm just happy to be working with Maurizio again at a big club like Chelsea which has so much history and wonderful team-mates. He helped me with his methods, but especially with his words.
"Before I came to Chelsea, I had the impression of a very good team, a great club, and of course you can see this is a very talented group of players. The training ground and all the facilities are at a great level – everything they have here is of the highest standard.
"It's a huge challenge to come and play in the Premier League and I'm going to give my all to help Chelsea."