World number one Novak Djokovic dealt a further blow to the hopes of the US Open going ahead after claiming it would be "impossible" to play under the "extreme" proposed safety protocols. The hard-court grand slam is due to begin at Flushing Meadows in New York on 31st August, but there are serious doubts over the tournament due to the ongoing coronavirus crisis. "I had a telephone conversation with the leaders of world tennis, there were talks about the continuation of the season, mostly about the US Open due in late August, but it is not known whether it will be held," the Serbian told Prva TV television. "The rules that they told us that we would have to respect to be there, to play at all, they are extreme.'' "We would not have access to Manhattan, we would have to sleep in hotels at the airport, to be tested twice or three times per week.'' "Also, we could bring one person to the club which is really impossible. I mean, you need your coach, then a fitness trainer, then a physiotherapist."