Updated: September 10, 2015 5:37 PM ET | Originally published: September 10, 2015 5:00 PM EDT

As Serena Williams enters the U.S. Open semifinals on Friday, following a rain delay, she’s making a run at tennis’ history books: if she successfully completes a calendar-year grand slam (consecutive wins at the Australian Open, French Open, Wimbledon, and U.S. Open) she’ll join the ranks of a handful of greats from the sport’s history.

Just five other singles players have ever met the challenge—though one did so twice, and several doubles players have managed too. From Don Budge in 1938, to Maureen Connolly in 1953, to Rod Laver in 1962 and 1969, to Margaret Court in 1970, to Steffi Graf in 1988, a calendar-year grand slam has been a rare feat. Here’s a look back at those tennis titans.

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Write to Lily Rothman at lily.rothman@time.com.

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