Novak Djokovic suffered a shock first-round US Open exit, losing to Argentina’s Mariano Navone in a four-hour, 36-minute five-set marathon
Physical issues hampered Djokovic, who vomited, appeared to cramp and required medical treatment during the match
The defeat raises fresh questions over Djokovic’s future, with the 24-time Grand Slam champion admitting he needs to address his ongoing problems