Sam Querrey

Resurgent del Potro tops No. 1 Djokovic in Olympic 1st round

Juan Martin del Potro sobbed into Novak Djokovic's shoulder, the two opponents locked in a long embrace at the net.

Djokovic would walk off the court weeping, too. For one man, a victory over the world's No. 1 tennis player that could resurrect a career he feared was over. For the other, a stunning loss that leaves him waiting four more long years for a chance at an Olympic singles gold medal.

Del Potro, the 2009 U.S. Open champion stalked by injuries ever since, won 7-6 (4), 7-6 (2) in the first round Sunday at the Rio de Janeiro Games. After three left wrist surgeries that had him contemplating retirement, he is ranked just 145th. But when the big Argentine is healthy...