Rod Laver

Rod Laver is the only player in tennis history to win all four Grand Slam titles in a single year twice, achieving the Grand Slam in 1962 and 1969. The Australian left-hander won 11 Grand Slam titles, but his 1969 season included 18 tournaments with a 93.2% win rate, 30% lighter than the typical Open-era champion's schedule. His total of 200 career titles is unmatched, outperforming #5 Steffi Graf's 107. Had professional tennis been open throughout his prime, his count would likely exceed 25 majors, a figure that surpasses #6 Pete Sampras's 14. Laver's versatility across eras is his strongest claim, as he remains the only player to win the Grand Slam in both amateur and Open tennis, a unique data point that no other legend on this list can match.