If people get jacked for the game, and look forward to watching it, and reminisce about all their memories from previous match ups, etc. it IS a rivalry game. That doesn't mean it has the same implications as other rivalry games (ex. Denver), but it is still a rivalry game. A rivalry game does not always have direct implications on the success of the that particular season.
A sports rivalry is intense competition between athletic teams or athletes, but not directly related to the formal sport and the practice thereof. This pressure of competition is felt by players, coaches, and management, but is perhaps felt strongest by the fans.