Conversation so far:
what occurred in 1972 to Ken Rosewall?
Rosewall won seven tournaments in 1972, including the depleted Australian Open and became the oldest Grand Slam male singles champion (37 years and 2 months old) in the open era
what was a tournement Ken Rosewall played in?
Rosewall won seven tournaments in 1972, including the depleted Australian Open

Question: who was an opponent?
Self-contained rewrite: who was an opponent of Ken Rosewall?