World No. 1 Novak Djokovic gives update on shoulder injury that forced him to retire in match against friend and 2016 US Open champion Stan Wawrinka.
US Open: Stan Wawrinka 'big-matches player', seeks fourth Grand Slam to cap comeback
World No. 1 Novak Djokovic gives update on shoulder injury that forced him to retire in match against friend and 2016 US Open champion Stan Wawrinka.
