Court workers dry Armstrong Stadium on the fourth day of the US Open Tennis Championships at the USTA National Tennis Center in Flushing Meadows, New York, USA, 301 September 2016. While inclement weather still stops all outer court play, the new retractable roof on Arthur Ashe Stadium for the first time allows the main court play to continue regardless of rainfall. EPA/JOHN G. MABANGLO

Rain falls on a tarp-covered Grandstand court on the fourth day of the US Open Tennis Championships at the USTA National Tennis Center in Flushing Meadows, New York, USA, 01 September 2016. While inclement weather still stops all outer court play, the new retractable roof on Arthur Ashe Stadium for the first time allows the main court play to continue regardless of rainfall. EPA/JOHN G. MABANGLO

Rain falls on the fourth day of the US Open Tennis Championships at the USTA National Tennis Center in Flushing Meadows, New York, USA, 01 September 2016. While inclement weather still stops all outer court play, the new retractable roof on Arthur Ashe Stadium for the first time allows the main court play to continue regardless of rainfall. EPA/JOHN G. MABANGLO

Fans seek shelter from the rain as play is suspended for the second time on all courts except Arthur Ashe on the fourth day of the US Open Tennis Championships at the USTA National Tennis Center in Flushing Meadows, New York, USA, 01 September 2016. The US Open runs through September 11. EPA/JOIHN G. MABANGLO

People huddle under a food stand in heavy rain on the fourth day of the US Open Tennis Championships at the USTA National Tennis Center in Flushing Meadows, New York, USA, 01 September 2016. The US Open runs through September 11. EPA/JUSTIN LANE