Almost five hours. One unprecedented upset. Denis Istomin stunned 6x AO champion Novak Djokovic in R2, playing a brilliant game that ended 7-6(8), 5-7, 2-6, 7-6 (5), 6-4. Did you tune in to this rollercoaster of a match? #USOpen _ #Tennis #Istomin #Melbourne #NovakDjokovic