Sixth Man
A superfan who believes that his fervent support of a team will have a direct influence on the outcome of a game said team may be involved in.
(Said superfan would be unlikely to ever be a member of said team, so concocting the notion of the 'sixth man' provides the illusion of personal validation, as such validation is, in the majority of cases, unattainable elsewhere)
(Said superfan would be unlikely to ever be a member of said team, so concocting the notion of the 'sixth man' provides the illusion of personal validation, as such validation is, in the majority of cases, unattainable elsewhere)
Superfan to curious journalist: 'Why am I stripped to my boxers and painted red? Because fans are as important to the game as each individual player on the court! People like me give those players the confidence and determination to win! Without people like me, they're nothing! They may as well not come! People like me are practically the sixth man!'