Which of the following was the greatest service returner in the history of the game of tennis: Andre Agassi or Martina Hingis?
Andre Agassi:  Generally considered by critics and fellow players to be one of the greatest tennis players of all time, Agassi has been called the greatest service returner in the history of the game. Martina Hingis: Martina Hingis (born 30 September 1980) is a Swiss professional tennis player, a former world No. 1 singles player and currently ranked world No. 2 in doubles by the WTA.
i don't know