Brajan Gruda and Danny Welbeck struck for Brighton as they won their third round tie 2-1 on Sunday.
Hurzeler said, “The players who came in deserved to play and they showed what they are capable of doing. We have shown a great deal of togetherness and I think it’s good to know that there are always players who can come in and make a difference. We will need everyone and for the players who came in it was an opportunity and they did really good.
“I’m very happy for the fans because they always give us great support. They had to travel twice to Manchester and it's not the closest place for us so I'm really happy for them, they spend a lot of money and time to support us. Hopefully they have a nice Sunday.”
On Brighton's performance, Hurzeler also said: “We were a bit lucky not to concede a goal in the first minutes but then we scored a nice goal and brought some calmness into our game. In the second half we controlled the game better.
“We have ambitions in the FA Cup but it’s do or die and we will have to be at our highest level whoever we play in the next round. Let’s see how far we can go.
"We always have the belief to compete with the best teams. You need to have this if you want to achieve something and we are a club with ambition.”