The Tartan Army's place at the finals in Mexico '86 depended almost entirely on Cooper striking the target, as the Scots were trailing the Welsh 1-0, thanks to an early Mark Hughes goal in the 13th minute, and only a draw or a win against their celtic cousins would guarantee Scotland one of the two qualifying places from Group VII.
As the 80th minute approached, Scotland's Stephen Nicol had set up a telling cross which was nodded on by Graeme Sharp and found David Speedie in the box - the little striker then sent the ball forward, and Welsh defender David Phillips was adjudged to have handled in the penalty area. Referee Johannes Keizer of Holland didn't hesitate in pointing to the spot, and the entire Scottish nation watched with nervous anticipation as Cooper stepped up and converted with cool confidence.
The Scotland coach, Jock Stein, watched from the dugout as the drama unfolded; looking pale and concerned, he leaned forward to catch a glimpse of the unfolding action on the pitch, but in the moments that followed the goal celebrations, as the crowd of Scotland fans in Ninian Park erupted in celebration, Stein remonstrated with an intrusive photographer near the dugout, then collapsed on the track and died shortly afterwards on the physiotherapy table in the away dressing room.
In those brief moments, probably the greatest light in Scottish football history was extinguished, and the game north of the border never truly recovered.
The Big Man
The only son of George and Jane Stein, John 'Jock' Stein was born in the small Lanarkshire mining village of Burnbank on 5 October 1922, during the global Depression that followed World War I.
Following a brief career as a labourer in a carpet factory, and later as a coal miner, he signed for Burnbank Athletic in 1940. However, his father had harboured ambitions of him playing for Blantyre Victoria, and possibly progress onwards to the professional club the family supported, Glasgow Rangers. He subsequently denied young John the opportunity to play for Athletic - so the red, white and blue strips of the Vics beckoned.