Joao Pedro scored both goals for the 2-0 win on Tuesday.
Maresca said afterwards: "It is a great achievement. It has been a fantastic season; top four in the Premier League, Conference League and now in the final of this competition - we are so, so happy.
"We know that we have players that are able to do that and we know we have to help them get in situations where they can do that and we know Joao can do this.
"I am very happy to be honest because I know how difficult it is with all the games. Premier League top four, we won the Conference League and now a final here - it is fantastic."
Jackson still our player
Maresca chose to start Pedro, with Nicolas Jackson coming on after the hour mark.
The manager also said: "Nicolas is our player. He is a striker. He played almost all the games last season. Now Joao started today but yes, he was OK."
On reaching the final, with Real Madrid to meet PSG in the other semifinal today, Maresca added: "They are both top teams. One won the Champions League this season, the other one last season. They are top teams but we are proud and we are happy to be there."