The Premier League leaders travel to the Etihad Stadium three points clear of City, whose European adventure ended in midweek after finishing bottom of their Champions League group.
Ferguson also expressed concern over his fragile defence and challenged his side to learn from their error-strewn display at Reading last weekend.
"If we win it will be one of our best ever results," Ferguson told MUTV.
"They are a really good, powerful team with massive players.
"It won't be easy and if we defend like we did at Reading we'll be in trouble.
"The important thing for us is to take lessons from the mistakes we're making and do something about it. We need to find a solution."