WASHINGTON, DC - JULY 31: Naomi Osaka of Japen returns a forehand shot to Bernarda Pera of the U.S. during Day Four of the Citi Open at the Rock Creek Tennis Center on July 31, 2018 in Washington, DC. (Photo by Mitchell Layton/Getty Images)
WASHINGTON, DC - JULY 31: Naomi Osaka of Japen returns a forehand shot to Bernarda Pera of the U.S. during Day Four of the Citi Open at the Rock Creek Tennis Center on July 31, 2018 in Washington, DC. (Photo by Mitchell Layton/Getty Images)