The Blues reached the final after victory over Palmeiras.
"We are happy. It was our objective to get to this stage of the competition, it’s very important for us," said Gusto.
"It was a tough game again so we are very happy. They had a lot of energy during the game so we just had to deal with that, and that’s what we did.
"I think during this tournament mental strength has been the most important thing and that’s why we are happy to be in the semi-final. We’ve shown that on the pitch in all the games we’ve had.
"It’s important to do something big, that’s what the coach asks of me on the pitch. So I just try to do my best to help the team as much as I can. That’s what I tried to do in this game and I’m happy we could win.
"We play a lot of games so one game can be bad and then the second can be much better. The most important thing is to deal with that and to just stay focused on the team and trying to give our best, to make yourself better game by game. That’s what I try to do."
Chelsea meet Fluminense in their semifinal and Gusto added, "It’s not enough yet, we still have a semi-final to play, to try to get to the final and try to win this trophy. Now we just have to believe in ourselves and to give our best."