The ex-Sunderland chairman believes the shift in momentum will be massive should United win.
He told Absolute Radio: "Yeah, I think this game really does stand out as, you know, the top game so far this season. When you look at the league table, if Manchester United are successful in the game after what happened in midweek and Man City's demise in Europe, it will be an amazing three points and a huge shift towards the title going back to Manchester United.
"I think that's the size, the sheer scale of the game. If it were to go Manchester City's way it's certainly not doom and gloom for Manchester United by any stretch of the imagination, it would hurt them and you still feel they'll be at us and will be making it very difficult for the rest of the year. Just in terms of the scale of the game I think it's amazing that we can say this before Christmas, but it would be such a momentous swing to one club or the other whoever wins it."