Novak Djokovic Knocks on the Door of a Very Exclusive Club

Only five players have achieved a Grand Slam, the last being Steffi Graf in 1988. Winning four major titles in a calendar year — the holy grail of tennis — is improbably hard.

It has been more than half a century since a man completed tennis’s Grand Slam, and that man is ready for company. “I don’t own the club; I’ve just enjoyed belonging to it,” Rod Laver, 83, said in a telephone interview last week from his home in Carlsbad, Calif. “If someone comes along to win all the four, I’d be the first to congratulate them.” The moment could be near. Novak Djokovic won the first three Grand Slam tournaments of the year and needs only to win the United States Open, which began on Monday in New York, to join Laver in the club.