Estevao, who will join Chelsea this month, scored for Palmeiras in Chelsea's 2-1 quarterfinal win on Friday.
Maresca said afterwards: "You can see he is a huge talent. You can see he is a fantastic player. The only thing now is when you come from South America or another part of the world to Europe you need to adapt.
"We are going to help him to adapt and first of all to enjoy football. We don't have any doubt, as he is so good, that he is going to be an important player for Chelsea."
You need to support him
Meanwhile, Palmeiras coach Abel Ferreira offered Maresca some advice on his departing attacker.
"You bought an amazing player but more than this you bought an amazing person," Ferreira said. "You need to take care of him.
"You need to embrace him and in the beginning for sure he will make mistakes. He is an amazing player with a lot of skill. He is a player who can win a game alone.
"With new players and a new coach he will grow as a player and a person. For sure he will need your support. It's the first time he will leave his country.
"In England the sun appears two or three times a year and the night comes early but with help Chelsea have the conditions to support him."