Injured Novak quits US Open

Novak Djokovic (right) concedes in the third set to Stan Wawrinka in their fourth-round match of the 2019 US Open in New York. (AFP)

Top-ranked defending champion Novak Djokovic retired with a shoulder injury after dropping the first two sets of Sunday’s US Open last-16 match against Stan Wawrinka.

Swiss 23rd seed and 2016 champion Wawrinka led Djokovic 6-4, 7-5, 2-1 when the Serb quit, having received treatment on his troublesome left shoulder before the start of the third set.