PERTH, AUSTRALIA - JANUARY 03: Stefanos Tsitsipas of Greece plays a backhand to Roger Federer of Switzerland during day six of the 2019 Hopman Cup at RAC Arena on January 03, 2019 in Perth, Australia. (Photo by Paul Kane/Getty Images)
PERTH, AUSTRALIA - JANUARY 03: Stefanos Tsitsipas of Greece plays a backhand to Roger Federer of Switzerland during day six of the 2019 Hopman Cup at RAC Arena on January 03, 2019 in Perth, Australia. (Photo by Paul Kane/Getty Images)