Member of 1972 Dolphins, Larry Csonka, celebrates Chiefs' loss - ESPN

On Sunday, Buffalo Bills fans excitedly watched their team dispatch the previously undefeated Kansas City Chiefs 30-21 in Orchard Park, New York. But they weren't the only fans of an AFC East team celebrating.

With the Chiefs — now 9-1 on the year — suffering their first loss of the season, the 1972 Miami Dolphins are still the only team in the Super Bowl era to complete a full regular season and postseason undefeated.

For Dolphins legend Larry Csonka, the occasion required raising a glass. He witnessed his team's legacy remain intact while part of a two-person watch party: himself and his former Syracuse teammate Nick Kish, a Buffalo-area native and longtime Bills fan.

Congrats <a href=«https://twitter.com/hashtag/BuffaloBills?src=hash&ref_src=» https:>#BuffaloBills

With my Syracuse teammate Nick Kish who's always been a <a href=«https://twitter.com/hashtag/Buffalo?src=hash&ref_src=» https:>#Buffalo fan. Tonight I am too