I remember when I was a kid having an obscure Everton video called 'Great Games, Great Goals 1984 - 1993'. It was a puzzling one because it missed all our great games from the 80's apart from the '84 cup final. It also had some dodgy choices for great games, including a 2-2 first leg draw with Crystal Palace in the League Cup.
Anyway, the save that always mesmerised me on that video was against City in the early 90's I believe. The City player was on the end of a cross to the far post, and it should of been a tap in. Southall got there for the save, but no goalkeeper had the right to get there. The commentators response was 'how did Southall get on the end of that one'. I must of watched that video countless times as a kid, mainly for the cup final, and that save has always stuck out for me. He simply shouldn't of been there, and I could never work how he did it.
Looking back now, it was probably that save that started Southall down the road of being my favourite player.