Rio targets morale-boosting Manchester United win
United head into Sunday's Old Trafford clash of the north west titans having fallen four points adrift of Premier League title favourites Chelsea.
"This kind of game is always good for galvanising spirit and belief," Ferdinand said. "You would be beating one of your closest rivals, so to win this game would be great for team morale. Hopefully it will put us on the crest of a wave."
Although their faults have been significant, United's general play had been impressive until the midweek stalemate with Rangers, when they failed completely to overcome break down the visitors' nine-man defence.
The loss of Antonio Valencia is a major blow, although, having made 10 changes to his line-up this week, Sir Alex Ferguson would not be guaranteed to select the stricken Ecuador wide man anyway.
But the pair will approach their task with confidence given the Spain star's recent poor form and Ferdinand believes United have every reason to be optimistic.
"There is a frustration with results but not with performance," he said. "We have been in commanding positions, so not to come away with six points from those two games is disappointing.
"But overall, we are pleased with the way we are playing. We have been scoring goals freely, including five in two games away from home. The main point is that we have to finish them off."
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