Byrne played for Liverpool in the 1965 FA Cup Final, which took place on 1 May at Wembley, with a broken collarbone. He suffered the injury as early as the third minute, but played on throughout the rest of the game and the whole of extra-time as Liverpool won the Cup for the very first time. The break happened after Byrne was challenged heftily by Leeds United's captain Bobby Collins, but, with substitutes still not permitted by the authorities in 1965, he had little choice but to carry on playing. The game went to extra-time and Byrne, despite the pain, kept making his familiar marauding runs down the left flank in joining the attack. Early on into the first period of extra time, he reached the by-line with the ball and pulled back a perfect cross for Roger Hunt to open the scoring. Leeds got back into the game and equalised through Billy Bremner but Liverpool were not to be denied as Ian St John headed home the winner late on during the second period securing Liverpools first ever FA Cup. Shankly spoke highly of Gerry in an interview after the final saying "It was a performance of raw courage from the boy".