New york - september 8, 2018: 2018 us open champion naomi osaka of japan in action während ihres finalen matches gegen serena williams im billie jean king national tennis center - Stockfoto & -bild

NEW YORK - SEPTEMBER 8, 2018: 2018 US Open champion Naomi Osaka of Japan in action during her final match against Serena Williams at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 6, 2018: Professional tennis player Naomi Osaka in action during her 2018 US Open semi-final match at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 6, 2018: Professional tennis player Naomi Osaka in action during her 2018 US Open semi-final match at Billie Jean King National Tennis Center

NEW YORK - AUGUST 29, 2017: Professional tennis player Madison Keys of United States in action during her US Open 2017 first round match at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 6, 2018: Professional tennis player Naomi Osaka celebrates victory after 2018 US Open semi-final match at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 6, 2018: Professional tennis player Naomi Osaka in action during her 2018 US Open semi-final match at Billie Jean King National Tennis Center

NEW YORK - AUGUST 31, 2019: Grand Slam Champion Naomi Osaka of Japan in action during her 2019 US Open third round match at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 8, 2018: 23-time Grand Slam champion Serena Williams in action during her 2018 US Open final match against Naomi Osaka at Billie Jean King National Tennis Center

NEW YORK - AUGUST 31, 2019: Grand Slam Champion Naomi Osaka of Japan in action during her 2019 US Open third round match at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 6, 2018: Professional tennis player Naomi Osaka in action during her 2018 US Open semi-final match at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 6, 2018: Professional tennis player Naomi Osaka in action during her 2018 US Open semi-final match at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 6, 2018: Professional tennis player Naomi Osaka in action during her 2018 US Open semi-final match at Billie Jean King National Tennis Center

NEW YORK - AUGUST 31, 2019: Professional tennis player 15-year-old Coco Gauff of United States in action during her 2019 US Open third round match at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 8, 2018: 23-time Grand Slam champion Serena Williams in action during her 2018 US Open final match against Naomi Osaka at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 6, 2018: Professional tennis player Naomi Osaka in action during her 2018 US Open semi-final match at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 6, 2018: Professional tennis player Naomi Osaka in action during her 2018 US Open semi-final match at Billie Jean King National Tennis Center

NEW YORK - AUGUST 31, 2019: Grand Slam Champion Naomi Osaka of Japan in action during her 2019 US Open third round match at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 8, 2018: 23-time Grand Slam champion Serena Williams in action during her 2018 US Open final match against Naomi Osaka at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 6, 2018: Professional tennis player Naomi Osaka in action during her 2018 US Open semi-final match at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 6, 2018: Professional tennis player Naomi Osaka in action during her 2018 US Open semi-final match at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 8, 2018: 23-time Grand Slam champion Serena Williams argues with chair umpire Carlos Ramos during her 2018 US Open final match at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 8, 2018: 23-time Grand Slam champion Serena Williams in action during her 2018 US Open final match against Naomi Osaka at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 1, 2018: Professional tennis player Naomi Osaka of Japan celebrates victory after her 2018 US Open round of 32 match at Billie Jean King National Tennis Center in New york

NEW YORK - SEPTEMBER 6, 2018: Professional tennis player Naomi Osaka in action during her 2018 US Open semi-final match at Billie Jean King National Tennis Center

NEW YORK - AUGUST 27, 2019: Grand Slam Champion Naomi Osaka of Japan celebrates victory after her 2019 US Open first round match at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 6, 2018: Professional tennis player Naomi Osaka in action during her 2018 US Open semi-final match at Billie Jean King National Tennis Center

RIO DE JANEIRO, BRAZIL - AUGUST 8, 2016: Olympic champions Serena Williams of United States in action during her singles round two match of the Rio 2016 Olympic Games at the Olympic Tennis Centre