NEW YORK, NY - SEPTEMBER 09: Juan Martin del Potro of Argentina reacts during his men's Singles finals match against Novak Djokovic of Serbia on Day Fourteen of the 2018 US Open at the USTA Billie Jean King National Tennis Center on September 9, 2018 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Sarah Stier/Getty Images)
