Cleveland Browns with a late score beat the the New York Yankees 14-9 in the first AAFC Championship Game
On December 22, 1946 On Sunday Dec 22, 1946 at Cleveland Municipal Stadium with 41,181 fans in Attendance, the Cleveland Browns with a late score beat the the New York Yankees 14-9 in the first AAFC Championship Game
Sources:
https://goldenrankings.com/AAFCchampionshipGame1946.htm