Νέα Υόρκη - 31 Αυγ: δεκαεπτά φορές grand slam πρωταθλητής roger federer χρησιμοποιώντας tweener κατά τη διάρκεια του τρίτου γύρου που ταιριάζουν στις ΗΠΑ ανοικτές 2014 στη Μπίλλι Τζίν Κίνγκ τένις εθνικό κέντρο στις 31 Αυγούστου, 2014 στη Νέα Υόρκη - Φωτογραφίες & Εικόνες Αρχείου

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

NEW YORK - SEPTEMBER 6, 2016: Professional tennis player Lukas Poulle of France using Tweener during round four match at US Open 2016 at Billie Jean King National Tennis Center

NEW YORK -SEPTEMBER 1, 2015: Seventeen times Grand Slam champion Roger Federer of Switzerland in action during first round US Open 2015 match at National Tennis Center in NY

NEW YORK- AUGUST 31: Grand Slam champion Roger Federer during third round match at US Open 2014 against Marcel Granollers at Billie Jean King National Tennis Center on August 31, 2014 in New York

NEW YORK - AUGUST 26: Professional tennis player Massimo Gonzales using Tweener during second round match at US Open 2014 at Billie Jean King National Tennis Center on August 26, 2014 in New York.

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

NEW YORK - AUGUST 24 Professional tennis player Fabio Fognini from Italy practices for US Open 2013 at Billie Jean King National Tennis Center on August 24, 2013 in New York

NEW YORK - AUGUST 29, 2016: Grand Slam champion Rafael Nadal of Spain in action during US Open 2016 first round match at Billie Jean King National Tennis Center

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

FLUSHING, NY -SEPTEMBER 2: Seventeen times Grand Slam champion Roger Federer during his fourth round match at US Open 2013 against Tommy Robredo at Billie Jean King National Tennis Center on September 2, 2013 in Flushing, NY

NEW YORK - SEPTEMBER 6, 2016: Professional tennis player Lukas Poulle of France using Tweener during round four match at US Open 2016 at Billie Jean King National Tennis Center

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

NEW YORK - AUGUST 31, 2014: Seventeen times Grand Slam champion Roger Federer during third round match at US Open 2014 at Billie Jean King National Tennis Center in New York

FLUSHING, NY - AUGUST 21: Professional tennis player Fernando Verdasco practices for US Open at Louis Armstrong Stadium at Billie Jean King National Tennis Center on August 21, 2012 in Flushing, NY.

NEW YORK - September 6 Seventeen times Grand Slam champion Roger Federer during semifinal match at US Open 2014 against Marin Cilic at Arthur Ashe Stadium on September 6, 2014 in New York

NEW YORK -SEPTEMBER 1, 2015: Seventeen times Grand Slam champion Roger Federer of Switzerland in action during first round US Open 2015 match at National Tennis Center in NY

FLUSHING, NY - AUGUST 19: Seventeen times Grand Slam champion Roger Federer practices for US Open 2013 at Arthur Ashe Stadium at Billie Jean King National Tennis Center on August 19, 2013 in Flushing, NY

FLUSHING, NY - AUGUST 29: Twelve times Grand Slam champion Rafael Nadal during his second round match at US Open 2013 against Rogerio Dutra Silva at Arthur Ashe Stadium on August 29, 2013 in Flushing, NY

NEW YORK - SEPTEMBER 7: Twelve times Grand Slam champion Rafael Nadal during his semifinal match at US Open 2013 against Richard Gasquet at Arthur Ashe Stadium on September 7, 2013 in Flushing, NY

NEW YORK - SEPTEMBER 6, 2014: Seventeen times Grand Slam champion Roger Federer during US Open 2014 semifinal match against Marin Cilic at Billie Jean King National Tennis Center in New York

NEW YORK -SEPTEMBER 1, 2015: Seventeen times Grand Slam champion Roger Federer of Switzerland in action during first round US Open 2015 match at National Tennis Center in NY

NEW YORK - AUGUST 24: Professional tennis player Janko Tipsarevic practices for US Open 2013 at Billie Jean King National Tennis Center on August 24, 2013 in New York

NEW YORK -SEPTEMBER 1, 2015: Seventeen times Grand Slam champion Roger Federer of Switzerland in action during first round US Open 2015 match at National Tennis Center in NY

NEW YORK -SEPTEMBER 1, 2015: Seventeen times Grand Slam champion Roger Federer of Switzerland in action during first round US Open 2015 match at National Tennis Center in NY

NEW YORK - SEPTEMBER 2, 2017: Professional tennis player Dominic Thiem of Austria in action during his US Open 2017 round 3 match at Billie Jean King National Tennis Center

NEW YORK - AUGUST 27 Seventeen times Grand Slam champion Roger Federer during his first round match at US Open 2013 against Grega Zemlja at Billie Jean King National Tennis Center on August 27, 2013 in Flushing, NY

NEW YORK - AUGUST 22, 2017: Nineteen times Grand Slam Champion Roger Federer of Switzerland practices for US Open 2017 at Billie Jean King National Tennis Center in New York

NEW YORK - AUGUST 29 Twelve times Grand Slam champion Rafael Nadal during second round match at US Open 2013 against Rogerio Dutra Silva at Arthur Ashe Stadium on August 29, 2013 in New York

NEW YORK - AUGUST 29, 2016: Grand Slam champion Rafael Nadal of Spain in action during US Open 2016 first round match at Billie Jean King National Tennis Center

FLUSHING, NY - AUGUST 29 Twelve times Grand Slam champion Rafael Nadal during his second round match at US Open 2013 against Rogerio Dutra Silva at Arthur Ashe Stadium on August 29, 2013 in Flushing, NY

NEW YORK- AUGUST 31: Grand Slam champion Roger Federer during third round match at US Open 2014 against Marcel Granollers at Billie Jean King National Tennis Center on August 31, 2014 in New York

NEW YORK - AUGUST 22, 2017: Fifteen times Grand Slam Champion Rafael Nadal of Spain practices for US Open 2017 at Billie Jean King National Tennis Center in New York