RIO DE JANERIO, BRAZIL - AUGUST 07: Novak Djokovic of Serbia (L) congratulates Juan Del Potro of Argentina after their men's singles match at the Rio 2016 Olympic Games, in Rio de Janeiro, Brazil on August 07, 2016. (Photo by Okan Ozer/Anadolu Agency/Getty Images)
ROME - MAY 05: Juan Martin Del Potro of Argentina breaks down with a back injury in the second game of the third set against Andy Murray of Great Britain during their first round match at the ATP Masters Series at the Foro Italico, on May 5, 2008 in Rome, Italy. (Photo by Clive Brunskill/Getty Images)
Argentina's Juan Martin Del Potro reacts during his men's singles gold medal tennis match against Britain's Andy Murray at the Olympic Tennis Centre of the Rio 2016 Olympic Games in Rio de Janeiro on August 14, 2016. / AFP / Luis Acosta (Photo credit should read LUIS ACOSTA/AFP/Getty Images)
