A key Series figure was Red Sox reliever Jim Willoughby. From his SABR bio page:
Willoughby was called on to put out a fire in the Game Seven. The score was tied, 3-3, in the top of the seventh inning. The bases were loaded and there were two outs with Johnny Bench at the plate. Willoughby retired Bench on a foul pop to catcher Fisk. Willoughby then pitched a 1-2-3 eighth inning. In the bottom of the inning, though, with none on, two out and the score still tied, manager Darrell Johnson pulled Willoughby for a pinch-hitter, the rusty Cecil Cooper. Cooper popped out to Pete Rose in foul territory.
Jim Burton, the rookie hurler who succeeded Willoughby, wound up giving up a run in the ninth and losing both the game and the Series. A story that has grown into a piece of urban folklore among Red Sox fans tells of a sportswriter going into a Boston area watering hole sometime after the World Series and encountering a solitary drinker mumbling to himself about Darrell Johnson, He never should have hit for Willoughby. Peter Gammons also has spun that tale.
When I heard the story, it included the detail that this occurred several
weeks after the Series, at a bar with the Patriots game on the TV but the fan's mind still back in Fenway Park.