Graf won 22 major singles titles and spent 377 weeks at world No.1. In 1988 she won all four majors and Olympic singles gold in the same year, the calendar-year Golden Slam. That is a specific achievement; it should not be confused with completing those titles across different seasons.

She beats Navratilova on her larger major total and that exceptional peak, but trails Serena under our longer-span preference. Readers who value one season above everything can put Graf first. Her second place rewards both dominant seasons and a large singles record, rather than treating Olympic gold as another Grand Slam title.

Source: Records.

Photo: Chris Eason · CC BY 2.0. Resized/compressed; license retained.