Cemented my life long man-crush on him when he came off the bench and scored a thunder-bolt equaliser against Crystal Palace in the FA Cup (well in my mind's eye its now a thunder-bolt equaliser, it was probably a 5 yard tap in). I've tracked the game down to 9th January 1979 but have never bee able to find any video footage.
As a footnote, circa 1983 when I was at Uni in Liverpool, I got into a conversation with a scouser whilst standing at the bar of the Brook House (pub near the halls of residence); when I told him that I was from Middlesbrough he said that his brother had played for Middlesbrough:- Billy Ashcroft.