United are currently four points behind their rivals in the league, but Van Gaal, who admits that he understands the intense rivalry between the clubs, believes that his side can grab all three points.
"This is the biggest derby that I shall manage," Van Gaal told reporters. "It is one of 38 [league] matches we have to play, but for the fans it is unbelievably big as a rivalry and I have felt that also with a lot of the players in the squad, but also especially with Ryan Giggs. When he presented the analysis on City, I felt more tension with him. It was good to see."
When asked if he expects United to win, Van Gaal said: "That is our goal, to win. It is possible, we are growing, we are developing ourselves. What we have seen of City in the last few matches was not so good. You never know."