The away goals rule is most often invoked in two-leg fixtures, where the initial result is determined by the aggregate score — i.e. the scores of both games are added together. In many competitions, the away goals rule is the first tie-breaker in such cases, with a penalty shootout as the second tie-breaker if each team has scored the same number of away goals. Rules vary as to whether the away goals rule applies only to the end of normal time of the second leg, or applies in extra time as well. It was first introduced by UEFA in the 1965–66 European Cup Winners' Cup.