Ahead of Sunday's Champions League decider at Nottingham Forest, Maresca was asked this morning about Spanish reports of Chelsea naming their price for Fernandez when in talks with Real Madrid this week.
The Italian said: "Enzo is very important for us. He is one of our captains, he is one of the leaders. This season has been very good and he can be even better next season, starting from the first day.
"I have nothing to say about speculation, his focus is on us and that is the most important thing."
On whether the Argentine midfielder is staying next season, Maresca simply said "yes".
Undone by a former Blue?
Meanwhile, at the City Ground on Sunday, Chelsea will face an in-form and former Blue, Callum Hudson-Odoi. Fifth-place Chelsea sit one point ahead of Forest in seventh.
Asked about the potential of being undone by a former Chelsea player, Maresca said: "At this moment he is a Forest player and I have no doubt he is going to try his best for his team and we just need to focus on our players and our team."
"The minute you join Chelsea you feel the pressure. You don't need to play these kind of games to feel more pressure. I've felt pressure since I've joined the club because it is a club where you have to win games. We won many games this season but we need one more."
Along with a battle to finish in the Premier League top five and Champions League qualification, Maresca also is preparing for next week's Europa Conference League final against Real Betis.
Quizzed about resting some players for the final, the manager insisted: "Now the focus is on Sunday's game.
"The next one is the most important one and then after that we can focus on Wednesday's game. I said this the other day, we don't have enough time to recover the energy so, for sure, we need to rotate and change things.
"We need to make some changes."
Away form worries
Chelsea, if they're to get a result at Forest, will have to buck a trend of poor form this season away from Stamford Bridge.
Maresca acknowledged: "It is something for sure, during the short break, we have to analyse. I also said many times I like to analyse game by game.
"Sometimes we played away and we didn't deserve to lose or even draw. But for sure if we struggle away, there is a reason why, and we are going to use the break to understand the reason why.
"On the other side, at home, we won almost all the games. So, there is also a good part as well."
No-one cares
Beyond Sunday and their Europa Conference League final, Maresca was also asked about next month's Club World Cup. The Blues boss admits player burnout is a concern.
"I am not thinking about next season, I am thinking about the next two games. But for sure there is a chance we have players that, because of the amount of games, can be injured or tired and then we'll see how we need to be.
"No-one cares about player welfare. If they are going to be tired, then they are not going to play. How are you going to manage that? It's simply like that. But I don't think there is much attention about players. Otherwise, it's not normal the amount of games they play."