Rivalry is defined as ”competition for the same objective or superiority in the same field.” In sports, teams and fans claim rivalries based on wins , losses, envy, and location. The New York Yankees and Boston Red Sox have traded blows since the 1900’s. Joe Frazier and Muhammad Ali forged a boxing rivalry that is hard to match. The Boston Celtics have remained blood rivals over time and eras.
The 49ers have their blood feuds. During the 90s, the Dallas Cowboys stood out as two titans at the top of the profession.