LONDON, ENGLAND - NOVEMBER 14: Novak Djokovic of Serbia hits a forehand against Roger Federer of Switzerland during Day Five of the Nitto ATP Finals at The O2 Arena on November 14, 2019 in London, England. (Photo by TPN/Getty Images)
LONDON, ENGLAND - NOVEMBER 14: Novak Djokovic of Serbia hits a forehand against Roger Federer of Switzerland during Day Five of the Nitto ATP Finals at The O2 Arena on November 14, 2019 in London, England. (Photo by TPN/Getty Images)