Christopher Nkunku struck a hat-trick, with Pedro Neto scoring a first goal for the club. There was also an own goal.
Maresca said afterwards: "Very happy with the performance, with the result. We did many changes, but the idea from the team was exactly the same. This has to be one of our targets, no matter how we are going to play, it is important that the identity of the team is always there.
"This type of game, I'm always worried a lot because they are tricky games. Football is full of these games, where you underestimate the other team; you concede goals and you concede chances but tonight I think the performance was very good and we showed how serious we are.
"We tried to prepare, as I said since I joined the club, we prepare the game on how the other team is defending or attacking so we try to find a solution. Palace was one plan, today was another plan.
"Today in the first half, Malo and Chilwell were playing like attacking midfielders on the ball to just create an overload in some part of the pitch so the guy with the ball has more options to pass, not just one, then he can decide. The idea is to give them more solutions and then they decide."
On Nkunku's hat-trick, he added: "It’s difficult to judge because last year I was not here. The only thing I can judge is that they’re (Nkunku and Nicolas Jackson) both doing fantastic. Not only because they score, but because they work off the ball. The way they sacrifice for the team.
"This is very important for them. This is a nice problem when you have two strikers that continue to score. Unfortunately, Marc Guiu is not scoring at the moment but hopefully soon he can. It’s nice you can decide which one and because they are in a good moment we can use them."