Juan Martin Del Potro of Argentina eyes the ball during the quarter-final match against Novak Djokovic of Serbia at the ATP Tennis Open tournament on May 20, 2017 at the Foro Italico in Rome. 
Serbia's Novak Djokovic, the second seed, cruised into the semi-finals of the Rome Masters Saturday after a rain-interrupted 6-1, 6-4 win over Juan del Potro. / AFP PHOTO / TIZIANA FABI        (Photo credit should read TIZIANA FABI/AFP via Getty Images)