Didn't we play at Wolves the day United let slip leads of 3-1 and 4-2 to draw with Everton? They were the early game, and, as a result, we went into ours at Molineux knowing that a victory would put matters back in our own hands only a fortnight after we'd been 8 points behind. We duly won 2-0, albeit with a team performance that wasn't especially convincing, to put us three points off the top but knowing that we could overtake our dear friends and neighbours by beating them in the next game (which we also did). The result confirmed Wolves's relegation, too. I vaguely recall that they had some gripe with our second goal but can't remember what it was without looking it up, which I don't have time to do.
As for best ever performance, I remember the Peter Barnes display against Chelsea in the 6-2 mentioned above. Their right back that day was Graham Wilkins, brother of Ray, and he got himself sent off in the second half. I'm sure he did it just to take himself out of the firing line. Barnes could be devastating when on song. Anyone remember the last 5 minutes against Standard Liege in the UEFA Cup, when he made 3 goals to turn a nervy 1-0 lead into a comfortable 4-0?