Real won 2-1, with Brahim Diaz and Lucas Vazquez scoring for the European giants, with Chelsea's goal coming via Noni Madueke.
Maresca later said: "One of my first meetings with the squad was about the number of goals we conceded last year with the defensive live being very high. It is something that we are trying to work on.
"Today offensively, once again, I think we were there because the patterns are there and we created chances. The problem has been defensively and when I say defensively, I don’t just mean the defensive line. All of the players.
"Overall, (the tour) is finished and now we head back to London where we will play against Inter Milan and then our first official game."
On the high defensive line, Maresca continued: "It is a habit. We are not working on playing with the defensive line higher. It is a habit from last year or from years ago. I don’t know. But we are trying to drop the defensive line by four or five metres so we have the advantage and don’t concede the balls in behind.
"Last season we conceded many goals with this problem and hopefully we can solve this problem very soon."
On his attacking approach, Maresca said: "The important thing for Christo (pher Nunku), we are contacting him between the lines because he is very good there.
"I think today we contacted with Christo and Enzo (Fernandez) many, many times and this is the most important thing to arrive there because with timing, we are going to take chances and score more goals."