Arsenal suffered heartache by being eliminated from this Years Champions league on away goals. Basically despite scoring the same amount of goals as their opponents over two matches their inferior amount of goals scored away from home caused them to lose out.
In the early years of European competition a match tied on aggregate resulted in a replay in a neutral ground.
The away goal rule was first used in the 1965-66 Uefa Cup Winners Cup. It was the 2nd round meeting of Honved Budapest of Hungary and Dukla Prague of the then Czechoslovakia. The first leg was played on the 3rd November 1965 in the Czech capital which Honved won 3-2. Seven days later Dukla travelled to Hungary and won the 2nd leg 2-1. Tied 4-4 on aggregate Honved became the first team to progress due to the away goal rule.
It wouldn’t be until 1970-71 before it was introduced into all European Competitions.
Debate continues as to whether away goals are good or bad for the game. Do teams become too conservative due to the risk of the away goal? There are also different arguments for which home team has the advantage.