Victory at Nottingham Forest saw Chelsea reach next season's competition ahead of tonight's Europa Conference League final against Real Betis.
Asked about his passionate response, Maresca insisted in Wroclaw: "First of all, I think it's a good feeling that the players react when there are some critics. So I think it's a good reaction from the players.
"Then Levi's (Colwill) reaction, my reaction, was just an outburst for the moment. And the reason why is because in our bad moment, or bad run during the season, in February, March, when we dropped points, many people were talking, and from our point of view, they were not talking in the right way.
"Probably if you ask them, they're going to say that from their point of view, they were talking the right way. But from our point of view, they were not talking in the right way. And the reason why is because, yes, we are young, yes, we are the youngest squad in the history of the Premier League, but at the same time, they are men.
"So I also use that critics to say 'guys, today is a chance that we can say that we are not young, we are mature enough, we can compete, and we can do the right things'. So I think Levi's reaction, my reaction, different players that they react, it was just an outburst."
Players needed convincing
On reaching the final tonight, Maresca admits some of his players had their doubts earlier in the season.
He said,"Probably the most complicated thing this season about the Conference has been to convince the players that for us it was the best competition in the world. And the reason why was because it was the competition that we were in.
"So every game has been difficult, especially because I needed to convince the players that we were able to drop nothing because you can lose points against any team. And we need to respect any team in Europe and any team that we face.
"And then I'm not focused about winning this competition or winning this trophy because my name, for sure I'm happy if we win, but I'm especially happy for the club, for the fans. And as you said, also because Chelsea can become the first club in Europe to win all the European competitions."
Maresca added: "The message in the last 48 hours has been, we did something important. But if we want to confirm that we are becoming an important club, we need to show the desire to win the title and to win the game. So, as you said, job done, fantastic, all happy. But tomorrow is a different game. It's a final. And it's a game that we want to win at any cost."