The Blues won on Tuesday night 1-0 thanks to a Richard Rios own goal. Chelsea also saw Joao Pedro sent off in injury-time.
Afterwards, Maresca said: "We needed for sure the win, the three points, for different reasons. I think first-half we controlled the game, we scored the goal, we created more chances and we didn't concede nothing unless two or three transitions, that is normal. And then second-half, for different reasons, we dropped.
"I think we have some players on the pitch that unfortunately are not 100%, but they are playing because we have seven or eight players out. But also I think it was good to win tonight, in any case, even if sometimes you need to learn to win in an ugly way, like the last minutes of the game."
On Pedro's dismissal, Maresca joked: "At least we learned how to win the game with the red card, that was the first one. Anyway, it was just two or three minutes to play. And now we have Tyrique play as a No.9 tonight, we have (Marc) Guiu on the bench that can play as a No.9, now we have time before Ajax game. But yeah, as you said, unfortunately another red card that we need to avoid."
We don't have a problem
Expanding on their issues with red cards, the Italian continued: "I always like to see one-v-one (meetings with players). I think Newcastle and Flamengo red card, they were for bad action. Then Sanchez (red card) is not for a bad action, it's just because he wants to defend the goal. Chalobah is because he wants to defend the goal.
"And tonight I think the second yellow card, Joao didn't even touch the other player, but the dynamic of the action is dangerous one. So for me personally, there is not any concern or any issue. It's just a moment that probably you need to take a different reason and avoid, for instance, Robert's after two, three minutes. Or even the other day, Brighton, 50 minutes.
"Sometimes it's better to concede the goal or the chance because then it's 11v11, you have 40 more minutes. So for me personally, there is not any problem behind."
On Alejandro Garnacho's performamnce, Maresca added: "Yes, tonight we start with Garna, that probably was the first game that he started. Ty is a No.9, and we know that he's not a No.9. Facu Buonanotte played an important role tonight. That's why for me tonight it's a nice feeling that it was important to win for different reasons.
"Injuries and the players that they are new with us. Garna was very good. I think (Jamie) Gittens also, he tried in the last 20 minutes when he was on. Both are going to be better and better game after game.