Out of all the "must win" games we have had that I can remember, we have won 2 of them. Battling to avoid the drop v Falkirk in 1993 and battling for 3rd v Aberdeen in 2008. The rest without exception have ended in major disappointment.
I'd go as far as to say the Aberdeen game is in my top 10 games ever. The atmosphere, tension, emotional and ultimately the feeling at the end really will take some beating.
That said, it's much much better to be battling for causes at the right end of the table!