The Blues won 2-0 thanks to goals from Enzo Fernandez and Pedro Neto.
Afterwards, Maresca said: "We are professional and have to adapt to any situation or environment.
"What’s important is the behaviour of the players, the attitude, and once again today, they showed how professional they are and the desire they have, because it was important to win today and also not to concede a goal.
"We finished the Premier League season and Conference League very strong defensively, without conceding many goals. Today we continued that and we want to stay with this attitude."
Happy with attacking options
Nico Jackson started in attack before new signing Liam Delap came on after halftime.
Maresca continued: "Both are very good No.9s and hopefully both can score goals and get assists like today, because I prefer to have four or five players who score ten or twelve goals each rather one striker who scores 40 goals. Enzo scored again today too, which is good.
"Last year we tried to use different threats, different weapons; we also we had two or three months where we were without Nico and Marc (Guiu). We tried to find different solutions but for sure, when you have two strikers like Nico and Liam, it’s a nice feeling as a head coach.
"You know you can choose one of them and it's going to be a good choice."