NEW YORK, NY - SEPTEMBER 06: Juan Martin del Potro (R) of Argentina shakes hands with Roger Federer (L) of Switzerland after their Men's Singles Quarterfinal match on Day Ten of the 2017 US Open at the USTA Billie Jean King National Tennis Center on September 6, 2017 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Al Bello/Getty Images)
