News Six-time Australian Open champ Roger Federer is upset by Stefanos Tsitsipas January 20, 2019January 20, 2019Sandra Harwitt, Special to USA TODAYComments Off on Six-time Australian Open champ Roger Federer is upset by Stefanos Tsitsipas The 20-year-old Stefanos Tsitsipas handed two-time defending champion Roger Federer a four-set loss.