RIO DE JANERIRO (AFP) - World number one tennis player Novak Djokovic was dumped out of the Olympics in the first round on Sunday (Aug 7), losing for the second successive Games to Juan Martin del Potro of Argentina.

Four years ago in London, the giant Del Potro defeated the Serb in the bronze medal match and he repeated the shock on Sunday in a stunning 7-6 (7/4), 7-6 (7/2) victory.

The 27-year-old Del Potro, whose ranking has slumped to 145 after a succession of wrist operations pushed him to the brink of retirement, started the day by getting stuck in an elevator for 40 minutes at the athletes village.

But that inconvenience did not shake the 2009 US Open champion out of his big-hitting stride as he shocked the top seed to set up a second-round clash with Portugal's Joao Sousa.