"One of the main things he said was that he doesn't want me to change," the Brazil-born Spain striker told the club's in-house television channel, Chelsea TV.
"It was Jose's and the club's decision to buy me and the reason they signed me was because of the way I played at Atletico (Madrid).
"I don't feel I have to change much
I just have to improve fine details to become a better player
Hopefully I will have a similar season to the last one."
Costa, 25, scored 36 goals last season, inspiring Atletico to a first La Liga title in 18 years -- as well as a place in the Champions League final -- and taking his tally at the club to 64 goals in 134 appearances.
It convinced Chelsea to part with around £32 million ($55 million, 40 million euros) in order to secure his services and Costa is confident that he can cope with the burden of expectation.
"I'd say to the fans that you need to be confident that I personally will fight for this club to make sure we are in contention to win as many trophies as possible," he said.
"I'm part of a great group here of players and we will do everything we can to give the fans what they want, and that's titles."
Costa's exploits in the Spanish capital turned him into one of Europe's most coveted strikers, but although he had no shortage of suitors, he said joining Chelsea had been a straightforward choice.
"It was an easy decision for me to make," he said.
"We have some of the best players in the world, the best manager in the world, and it's a club with great history.
"I want to improve, not only as a player but as an individual, and I believe this is the perfect place for me to do that
That's the reason I chose Chelsea and why I want to defend this shirt."
Source : AFP
Source: AFP