I was at a Jays v Sox game back in '89 I think. Jays won handily, but the following game was a massive collapse by the Red Sox. How bad? You can still find article on how the Red Sox blew a 9 or 10 run lead (looks it up... 10 run). Back in the days when the Lions, Jays, and Sox were swapping spots atop the AL East.
I actually remember watching this game on TV with my Dad. I think Felix Jose had an inside the park grand slam (or that might have been another game). But yeah, that was quite a comeback/meltdown. Also, I think later that same week the Blue Jays opened the Sky Dome (they were still playing in Exhibition Stadium until Sky Dome was complete).