Coventry 1 - 3 Everton. 2000/01 season.
We were in the middle of a massive injury/illness crisis with a pretty poor team anyway. Alex Cleland and Niclas Alexandersson got rare starts but both got subbed off after about 20-30 minutes due to injury leaving us to rely on teenagers Phil Jevons and Peter Clarke who hard barely played at all before that for the rest of the game. We started a midfield of Idan Tal, Scott Gemmill, Mark Pembridge and Alexandersson we wasn't expecting much at all.
We got loads of tickets for some reason and took loads down there and we absolutely battered them and were 3-0 up after half an hour with goals from Gemmill, Cadamarteri and Kevin Campbell. Even their goal was nice in hindsight for us, a penalty from Lee Carsley!
Got the nice bonus of driving down the motorway alongside the team bus on the way home too and the players were all giving us the "get in" fists (You know what I mean..).
Just one of those boss unexpected (and badly needed) wins.