The rivalry between the two North-West clubs is one of the fiercest in world football, and this weekend marks the first meeting of the season.
United head to Anfield with a better record as they are unbeaten in 10 games in all competitions, while Liverpool have claimed just a single victory in their last seven outings.
"It's for three points, not four," Sky Sports News quotes Mourinho as saying. "Maybe if we were in a moment of the season where it was a duel between two teams it would mean more but it's not the case.
"At the same time, in these kinds of matches, every single moment plays a part. We are playing against a good team with very good players."