How it unfolded
Graf, 19, reached New York after beating Chris Evert 6-1, 7-6 at the Australian Open, crushing Natasha Zvereva 6-0, 6-0 in 32 minutes at Roland Garros, and defeating Martina Navratilova 5-7, 6-2, 6-1 at Wimbledon. Gabriela Sabatini of Argentina stood between her and the calendar Slam. Graf took the first set 6-3; Sabatini's topspin rallies reclaimed the second 6-3. In the third Graf hammered inside-out forehands and finished 6-1 — the third women's calendar Grand Slam after Margaret Court in 1970, and the first in 18 years. Three weeks later at Seoul, tennis's return as a full Olympic medal sport after 64 years, she beat Sabatini again 6-3, 6-3 for gold. Four majors plus Olympic gold in one year was first called a Golden Slam — still unique across both draws. Graf finished 1988 at 72–3.
Why it still matters
The season defines the upper limit of dominance. No one has repeated the Golden Slam; Djokovic needed a full career to collect the same five titles. That it landed in Seoul's first Olympic tennis year also marks when Olympic tennis gained its present stature.