
Nick Kyrgios is into the US Open quarter-finals after a tough, four-set win over defending champion Daniil Medvedev.
In a fiery encounter, Kyrgios risked being defaulted and overcame a running verbal battle with the chair umpire and a potentially catastrophic play before downing the world No.1 7-6 (13-11) 3-6 6-3 6-2 on Monday morning (Australian time).