Nowy Jork - 22 Sierpień 2018: 13-czas Grand Slam Championem Novak Djokovic Serbii praktyk do 2018 roku Us Open w Billie Jean King National Tennis - Zdjęcie stockowe & obraz

NEW YORK - AUGUST 22, 2018: 13-time Grand Slam champion Novak Djokovic of Serbia practices for the 2018 US Open at Billie Jean King National Tennis

NEW YORK - AUGUST 24: Six times Grand Slam champion Novak Djokovic practices for US Open 2014 at Billie Jean King National Tennis Center on August 24 , 2014 in New York

NEW YORK - AUGUST 22, 2018: 13-time Grand Slam champion Novak Djokovic of Serbia practices for the 2018 US Open at Billie Jean King National Tennis

NEW YORK - AUGUST 21: Six times Grand Slam champion Novak Djokovic practices for US Open 2014 at Billie Jean King National Tennis Center on August 21, 2014 in New York

NEW YORK - AUGUST 22, 2018: 13-time Grand Slam champion Novak Djokovic of Serbia practices for the 2018 US Open at Billie Jean King National Tennis

NEW YORK - AUGUST 22, 2018: 13-time Grand Slam champion Novak Djokovic of Serbia practices for the 2018 US Open at Billie Jean King National Tennis

NEW YORK - AUGUST 24: Six times Grand Slam champion Novak Djokovic practices for US Open 2014 at Billie Jean King National Tennis Center on August 24 , 2014 in New York

NEW YORK - AUGUST 22, 2018: 13-time Grand Slam champion Novak Djokovic of Serbia practices for the 2018 US Open at Billie Jean King National Tennis

NEW YORK - AUGUST 22, 2018: 13-time Grand Slam champion Novak Djokovic of Serbia practices for the 2018 US Open at Billie Jean King National Tennis

NEW YORK - AUGUST 22, 2018: 13-time Grand Slam champion Novak Djokovic of Serbia practices for the 2018 US Open at Billie Jean King National Tennis

NEW YORK- SEPTEMBER 3, 2016: Twelve times Grand Slam champion Novak Djokovic of Serbia practices for for US Open 2016 at Billie Jean King National Tennis Center in New York

NEW YORK - AUGUST 22, 2018: 13-time Grand Slam champion Novak Djokovic of Serbia practices for the 2018 US Open at Billie Jean King National Tennis

NEW YORK - AUGUST 22, 2018: 13-time Grand Slam champion Novak Djokovic of Serbia practices for the 2018 US Open at Billie Jean King National Tennis

NEW YORK - AUGUST 24: Six times Grand Slam champion Novak Djokovic practices for US Open 2014 at Billie Jean King National Tennis Center on August 24 , 2014 in New York

NEW YORK - AUGUST 27, 2017: Professional tennis player Lucas Pouille of France practices for US Open 2017 at Billie Jean King National Tennis Center in New York

NEW YORK - AUGUST 20: Professional tennis player Robby Ginepri during qualifying match match at US Open 2013 at Billie Jean King National Tennis Center on August 20, 2013 in New York

NEW YORK- SEPTEMBER 3, 2016: Twelve times Grand Slam champion Novak Djokovic of Serbia practices for for US Open 2016 at Billie Jean King National Tennis Center in New York

NEW YORK - AUGUST 22, 2018: 13-time Grand Slam champion Novak Djokovic of Serbia practices for the 2018 US Open at Billie Jean King National Tennis

NEW YORK - AUGUST 22, 2018: 13-time Grand Slam champion Novak Djokovic of Serbia practices for the 2018 US Open at Billie Jean King National Tennis

NEW YORK - AUGUST 22, 2018: 13-time Grand Slam champion Novak Djokovic of Serbia practices for the 2018 US Open at Billie Jean King National Tennis

NEW YORK- SEPTEMBER 3, 2016: Twelve times Grand Slam champion Novak Djokovic of Serbia practices for for US Open 2016 at Billie Jean King National Tennis Center in New York

NEW YORK - AUGUST 23: Professional tennis player Grigor Dimitrov from Bulgaria practices for US Open 2014 at Billie Jean King National Tennis Center on August 23 , 2014 in New York

NEW YORK - AUGUST 25, 2015: Fourteen times Grand Slam Champion Rafael Nadal of Spain practices for US Open 2015 at Billie Jean King National Tennis Center in New York

NEW YORK - AUGUST 22, 2018: 13-time Grand Slam champion Novak Djokovic of Serbia practices for the 2018 US Open at Billie Jean King National Tennis

NEW YORK - AUGUST 25, 2015: Fourteen times Grand Slam Champion Rafael Nadal of Spain practices for US Open 2015 at Billie Jean King National Tennis Center in New York

NEW YORK - AUGUST 21: Grand Slam Champion Andy Murray practices for US Open 2014 at Billie Jean King National Tennis Center on August 21, 2014 in New York

NEW YORK - AUGUST 24: Six times Grand Slam champion Novak Djokovic practices for US Open 2014 at Billie Jean King National Tennis Center on August 24 , 2014 in New York

FLUSHING, NY - AUGUST 24: Professional tennis player Ricardas Berankis practices for US Open 2013 at Billie Jean King National Tennis Center on August 24, 2013 in Flushing, NY