The two Manchester outfits square up to each other on Sunday in the 13:30 kick off at the Etihad Stadium and as you would expect, both sides will be going hell for leather to get one over on their fierce rivals.
A win for City will tighten things at the top, while if United come away with all three points, they go six clear at the top.
Speaking to reporters, Ferguson said: "I think the two sides have that gap over Chelsea, Arsenal and Tottenham. It will be difficult to think the two of us will collapse. I think it will be between the two of us."
Should United end City's unbeaten start to the season on Sunday, Ferguson said a six-point advantage at this stage would not mean that much.
"It won't mean a great deal because there's such a long way to go until the end of the season," he added.
"You can never be sure and you can lose to anyone. That's the kind of league we're in. It's a tough league."
Source: United Mad