Watch: Djokovic in tears during his first-round US Open defeat to Navone

Novak Djokovic was knocked out in the first round of the US Open by Mariano Navone in a four-hour, 36-minute five-set battle. The 39-year-old struggled with physical issues, including cramps and back pain, while making 70 unforced errors. Djokovic also became emotional during the match, with tears h…