Steffi who achieved a Golden Slam in 1988 (4)

I believe the answer is:

graf

(Other definitions for graf that I've seen before include "German tennis player, b. 1969" , "Noted tennis player" , "German count - German tennis player" , "Steffi --, tennis champion" , "Seven-times women's Wimbledon champion, b. 1969" .)

I've seen this clue in The New York Times.

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