If Novak Djokovic wins the French Open, he'll be the third athlete in four years to dominate on all three grand-slam surfaces—the result of subtle changes that favor long, dramatic matches between superstars.
When Andre Agassi won the French Open in 1999, he earned the distinction of being the first player in the Open Era of men's tennis (1968-2008) to win every grand-slam tournament on the sport's three different playing surfaces: grass, clay, and hard courts. Rod Laver was the first Open Era player to win each title or complete a career grand slam, but the difference between Laver and Agassi's achievements—besides the fact Laver won all four tournaments in the same calendar year—is that Laver did it when every grand slam except the French Open was played on grass, whereas Agassi won the U.S. Open and the Australian Open on the hard-court surfaces those tournaments currently employ.
Agassi's accomplishment stands as a testament to his incredible talent, since tennis used to be a game that catered to different playing styles depending upon the surface on which it was played. Throughout most of the Open Era, those little yellow tennis balls bounced very differently on the lawns of the All England Lawn Tennis and Croquet Club, the red clay of Roland Garros, and the hard courts at the Australian and U.S. opens, and many great players failed to reach the pinnacle of their sport on every surface. Bjorn Borg, who utterly dominated Wimbledon and the French Open from the mid '70s to the early '80s, was never able to win on the hard courts at the U.S. Open. Pete Sampras won a then-record 14 grand slam titles but famously struggled on the Roland Garros' clay—his best finish at the French Open was a semi-final appearance in 1996.