That 1970 FA Cup Final is notorious for being one of the most physical of all time, it saw Harris come into his own in the role of both inspirational leader and uncompromising tackler. With Leeds having taken a 2–1 lead at Wembley with just six minutes remaining, it was his quick free kick which led to Ian Hutchinson's headed equaliser to take the game to a replay. During the replay at Old Trafford his late tackle on Leeds' playmaker Eddie Gray after just eight minutes (just one of many late tackles committed by both sides), left the latter a virtual passenger for the rest of the match: Chelsea eventually won 2–1 after extra-time.