An own goal, plus efforts from Estevao Willian and Liam Delap saw Chelsea earn the impressive victory, with Ronald Araujo seeing red for Barca just before the break.
Asked about the significance of defeating the LaLiga champions, Maresca said: "For me, personally, as you said, it's a big win, especially because the other team was Barcelona. But nothing changed in terms of what team we are, what we can achieve. So for sure it's important tonight's game, but no more than that. It's finished, now focus on the next one that is difficult again."
On his goalscorers, Maresca also said: "Estevao, he had a very good game, not only for the goal, because he helped a lot the team in the way we were pressing. Liam also needed this kind of moment, goal, because he's back from injury. I think against Burnley, he was quite good, but he's a No.9, he's a striker, and they need a goal. But tonight we scored three disallowed goals. So I think we created enough to win the game.
"The feeling was very good, especially as you said, because it was at home with our fans. It's always nice to share this kind of moment. But now, I told the players, next 48 hours, completely switch off, have a rest, recovery energy, because then Sunday we have Arsenal. But my message after the game was just recover energy, that in this moment is the most important thing. And then from Friday we start to think about Arsenal."
Maresca admits his young team is growing in Europe thanks to the silverware won last season. Lifting the Europa Conference League and Club World Cup trophies have increased the belief amongst the players when facing matches like Tuesday night.
The Italian explained, "For sure, winning the Club World Cup gives the players the confidence that they need. Last year, we were playing in the Conference League, and I said many times that for me personally, if you want to build a winning mentality, there is only one way. Winning games. Because otherwise, if you don't win games, it's difficult to convince the players, guys, we are building a winning mentality.
"But when we don't win, it's difficult. So the only way in any competition, Conference League, Champions League this season, Premier League, FA Cup, Carabao Cup, is to win games. It's the only way to build the winning mentality. And I think the Conference League and the Club World Cup last season helped a lot. And now we are trying to do exactly the same. For sure, the players are better players in this moment compared to last season, because we spent more time together.