For 56 years, drawn two-legged ties in the European Cup/Champions League, UEFA Cup/Europa League and the old Cup Winners’ Cup have been settled on a simple premise: whichever side scores more goals away from home goes through; in theory, they counted double.
Introduced in the days before wall-to-wall coverage of European football helped lessen its mystery, and when trips to far-flung corners of the continent were much more arduous than they are now, the original aim of the rule was to encourage teams to be more positive away from home.
It’s led to some truly dramatic moments over the years, with a single goal able to shift the momentum of a tie.