New york - 8. september 2015: 21-malige Grand-Slam-Siegerin serena williams in Aktion während ihres Viertelfinalspiels gegen venus williams bei den us open 2015 im National Tennis Center in new york - Stockfoto & -bild

NEW YORK - SEPTEMBER 8, 2015: Twenty one times Grand Slam champion Serena Williams in action during her quarterfinal match against Venus Williams at US Open 2015 at National Tennis Center in New York

NEW YORK - AUGUST 31, 2015: Twenty one times Grand Slam champion Serena Williams in action during first round match at US Open 2015 at National Tennis Center in New York

NEW YORK - SEPTEMBER 8, 2015: Twenty one times Grand Slam champion Serena Williams in action during her quarterfinal match against Venus Williams at US Open 2015 at National Tennis Center in New York

NEW YORK - SEPTEMBER 8, 2015: Twenty one times Grand Slam champion Serena Williams in action during her quarterfinal match against Venus Williams at US Open 2015 at National Tennis Center in New York

NEW YORK - AUGUST 30, 2016: Grand Slam champion Serena Williams in action during first round match at US Open 2016 at Billie Jean King National Tennis Center in New York

NEW YORK - AUGUST 27, 2018: 23-time Grand Slam champion Serena Williams in action during her 2018 US Open first round match at Billie Jean King National Tennis Center

NEW YORK - AUGUST 30, 2016: Grand Slam champion Serena Williams in action during her first round match at US Open 2016 at Billie Jean King National Tennis Center in New York

NEW YORK - SEPTEMBER 8, 2015: Twenty one times Grand Slam champion Serena Williams in action during her quarterfinal match against Venus Williams at US Open 2015 at National Tennis Center in New York

NEW YORK - AUGUST 26, 2019: Grand Slam champion Serena Williams in action during 2019 US Open first round match against Maria Sharapova at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 6, 2018: 23-time Grand Slam champion Serena Williams in action during her 2018 US Open semi-final match at Billie Jean King National Tennis Center

NEW YORK- SEPTEMBER 1: Grand Slam champion Serena Williams celebrates victory after fourth round match at US Open 2013 against Sloane Stephens at Billie Jean King National Tennis Center on September 1, 2013 in New York

NEW YORK - SEPTEMBER 3, 2017: Grand Slam champion Venus Williams of United States in action during her round 4 match at 2017 US Open at Billie Jean King National Tennis Center in New York

NEW YORK - AUGUST 30, 2016: Grand Slam champion Serena Williams in action during first round match at US Open 2016 at Billie Jean King National Tennis Center in New York

NEW YORK - AUGUST 26, 2019: Grand Slam champion Serena Williams of United States in action during 2019 US Open semi-final match against Elina Svitolina at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 8, 2015: Twenty one times Grand Slam champion Serena Williams celebrates victory after her quarterfinal match against Venus Williams at US Open 2015 in New York

NEW YORK - SEPTEMBER 6, 2018: 23-time Grand Slam champion Serena Williams 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, 2015: Twenty one times Grand Slam champion Serena Williams in action during her quarterfinal match against Venus Williams at US Open 2015 at National Tennis Center in New York

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 3, 2016: Grand Slam champion Serena Williams of United States in action during her round three match at US Open 2016 at Billie Jean King National Tennis Center in New York

NEW YORK - SEPTEMBER 8, 2015: Twenty one times Grand Slam champion Serena Williams in action during her quarterfinal match against Venus Williams at US Open 2015 at National Tennis Center in New York

NEW YORK - SEPTEMBER 2, 2018: 23-time Grand Slam champion Serena Williams in action during her 2018 US Open round of 16 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 5, 2016: Grand Slam champion Serena Williams of United States in action during her round four match at US Open 2016 at Billie Jean King National Tennis Center in New York

NEW YORK - AUGUST 29 Sixteen times Grand Slam champion Serena Williams during first round doubles match with teammate Venus Williams at US Open 2013 at Billie Jean King National Tennis Center on August 29, 2013 in New York

NEW YORK - SEPTEMBER 8, 2018: 23-time Grand Slam champion Serena Williams broke tennis racket during her 2018 US Open final match at Billie Jean King National Tennis Center

NEW YORK - AUGUST 27, 2018: 23-time Grand Slam champion Serena Williams in action during her 2018 US Open first round match at Billie Jean King National Tennis Center

FLUSHING, NY - AUGUST 29 Sixteen times Grand Slam champion Serena Williams during her first round doubles match with teammate Venus Williams at US Open 2013 at Billie Jean King National Tennis Center on August 29, 2013 in Flushing, NY

NEW YORK - AUGUST 30, 2016: Grand Slam champion Serena Williams in action during first round match at US Open 2016 at Billie Jean King National Tennis Center in New York

NEW YORK - SEPTEMBER 6, 2018: 23-time Grand Slam champion Serena Williams in action during her 2018 US Open semi-final match at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 2, 2018: 23-time Grand Slam champion Serena Williams in action during her 2018 US Open round of 16 match at Billie Jean King National Tennis Center

NEW YORK - SEPTEMBER 1, 2019: Grand Slam champion Serena Williams in action during her 2019 US Open round of 16 match at Billie Jean King National Tennis Center