City lost 3-2 to United at home earlier this month.
Silva told The Sun: "The derby game is always special but this one will be like a final for us. We need to arrive there still alive in the league race.
"But the title won't just be won that day. To repeat our success we need to win in every stadium. There can be no more excuses after our defeat at Sunderland.
"Never could we believe at this stage we'd find ourselves seven points behind United but it's happened. And, once again, although we face a complicated game at Norwich it's a game we simply must win."