City skipper Vincent Kompany has already spoken of his desire to make the game into a one-off championship of Manchester - something Ferguson understands.
"It'll be a big game for City - they'll want to come and derail us for a spell," the United boss said.
"I can understand their motivation - we'd probably have the same thing.
"There will still be a great intensity about the game. It's the only game and it will be shown all over the world.
"That does seep into the fabric of what the game will be like for both teams. You can't dismiss that."