(AP Photo/Kin Cheung) Kin CheungĪustralia's Ashleigh Barty, left, is congratulated by Greece's Maria Sakkari after winning their third round match at the Australian Open tennis championships in Melbourne, Australia, Friday, Jan. United States' Taylor Fritz plays a forehand return to Switzerland's Roger Federer during their third round match at the Australian Open tennis championships in Melbourne, Australia, Friday, Jan. Switzerland's Roger Federer makes a forehand return to United States' Taylor Fritz during their third round match at the Australian Open tennis championships in Melbourne, Australia, Friday, Jan. (AP Photo/Mark Schiefelbein) Mark Schiefelbein

Greece's Stefanos Tsitsipas, left, is congratulated by Georgia's Nikoloz Basilashvili after winning their third round match at the Australian Open tennis championships in Melbourne, Australia, Friday, Jan.

Greece's Stefanos Tsitsipas celebrates after defeating Georgia's Nikoloz Basilashvili during their third round match at the Australian Open tennis championships in Melbourne, Australia, Friday, Jan.

Roger Federer wipes the sweat from his face during his third round match against Taylor Fritz at the Australian Open, Thursday.