US Open 2019: Djokovic defence over as he retires from Wawrinka clash

New York, September 2: Novak Djokovic is out of the US Open after retiring from his fourth-round match with Stan Wawrinka.

The Serbian battled a shoulder injury in his second-round win over Juan Ignacio Londero but appeared to suggest his condition had improved after a third-round defeat of Denis Kudla.

However, the world number one was second best throughout against the 2016 champion and called it quits after he dropped his serve to give Wawrinka a 6-4 7-5 2-1 lead in the third.

Wawrinka, who is in pursuit of his fourth major title, will play Daniil Medvedev for a place in the semi-finals.