Tennis Tennis US Open: Djokovic's title defence ends, retires from Wawrinka clash World number one Novak Djokovic saw his US Open defence end as he retired in the third set against Stan Wawrinka. Nicholas McGee New York 02 September, 2019 08:44 IST Novak Djokovic could not continue his title defense at the US Open owing to persistent trouble in his left shoulder. - Getty Images Nicholas McGee New York 02 September, 2019 08:44 IST 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 semifinals. 6-4, 7-5, 2-1 (ret.)@stanwawrinka returns to the QF after Djokovic retires from the match.#USOpen pic.twitter.com/3cGoWzcE0b— US Open Tennis (@usopen) September 2, 2019 Read more stories on Tennis. For more updates, follow Sportstar on :