I think it was the pre match billing. Dumbarton (Scottish Cup Winners) beat Blackburn Olympic (FA Cup Winners) 6-1 at Boghead for the 'Championship of Britain'
Renton's victory, also in an unnoficial match, was at a time when Scottish clubs had been banned from competing in the FA cup. It was at a neutral venue, Cathkin Braes (or Hampden as it was called at the time) and was billed as 'Championship of Britain and the World'.
I remember Sons playing WBA in a centenary of Renton's triumph - a pre season friendly. Gordon Mills, by that time 26 and who had been a top junior striker was a trialist for Sons that day. He was about two years younger than me and both he and his older brother Archie were great Sons fans. We didn't sign him. Our loss was Auchinleck Talbot's gain.