Primus spoke of the noise levels created in the past, leaving the players feeling "invincible".
He told The News: "The times we've played Man United and beat them have been big moments in our season.
"The first year we were in that position where we needed to take points. We went out there with a fearless attitude because the expectancy was on them to win. When you go out there with no pressure you can play with freedom.
"The atmosphere was a big part of what got us results. We need that now. They drive you on and make you believe that you can go and win the game.
"That is always the case. When you have that feeling about you, you do really feel invincible."