Men’s tennis is relishing one of those golden periods when either a clutch of players, or two in particular, raise the sport to a new level by virtue of their brilliance and keen rivalry.

Before 1968, tennis had long been devalued by the division between professionals and amateurs, resulting in the sport’s big events being deprived of its best players. Since the “open” era began 40 years ago, however, the game has enjoyed the unalloyed glories of Rod Laver and Ken Rosewall, and then two periods defined by their chief rivalries: those of Bjorn Borg and John McEnroe, followed by Pete Sampras and Andre Agassi.