How it unfolded
Borg, 24, sought a fifth straight title; McEnroe, 21, reached his first Wimbledon final after beating Jimmy Connors in the semis to a hostile crowd. McEnroe seized the first set 6-1; Borg reversed the next two 7-5, 6-3. The fourth-set tiebreak became myth: 34 points over roughly 22 minutes, five championship points saved by McEnroe, finally won 18-16 to force a fifth set. Borg should have collapsed; instead he was never broken in the decider and broke McEnroe at 6-6 for 8-6 in 3 hours 53 minutes — a fifth Wimbledon title and a 35-match streak at the Championships. McEnroe won the US Open final two months later and ended Borg's 41-match Wimbledon run in the 1981 final. Borg effectively retired at 26 the following year.
Why it still matters
Often called colour television tennis's aesthetic peak; the fourth-set tiebreak is still "that tiebreak" without explanation. Ice-cool Swede versus explosive New Yorker showed tennis as personality theatre and became the narrative template for every great rivalry since.