Rodrigo Muniz, Raul Jimenez, Joachim Andersen and Timothy Castagne struck the goals on the night.
Silva said: "The most important thing was to play in the next round and we knew this was a game we needed to win. It's a special competition and it does not matter if they are in the Championship, League One or the Premier League. Every team has a dream and wants to shine in this competition.
"The players did really well and it was a really well deserved win from the first minute and we took control of the game. They did a great strike (to equalise) but we had to keep the calmness then we took control of the game. We then scored three goals and deserved to be in the next round.
"It (the FA Cup) is really important for us. It does not make any difference from one competition to the other. It's a great competition, the only strange thing is to be playing on a Thursday night.
"We will embrace the challenge and each game is for us to try to win. We want to do well. All the teams have the dream to be in the last game of the season in the final. It's a long way to go and we have to really fight hard. The ambition is really big but we have to go game by game."