I have to go with the Chambliss HR as it was one of my first great Yankee memories as it likely is for anyone born in that late 60s/early 70s period.

The paper had a list of Yankee post season game ending HR this morning, and amazingly, almost three quarters of them were done by the leadoff batter of the inning as Teixiera’s was last night and Chambliss’ was back in ‘76.

Brosius because:

1- Even I’m too young to remember anything before 1965.
2- Yankees likely win current Twins series even if they lost last night.
3- Chambliss is a close 2nd because: His HR put the Yanks into the WS but the game was tied. Yanks were losing WS game when Brosius hit the HR.