Serena and Venus Williams lost an Olympic doubles match for the first time ever as they were stunned in the opening round of the Rio de Janeiro Games by the Czech Republic's Lucie Safarova and Barbora Strycova 6-3 6-4.
The Williams sisters entered Sunday's match with a 15-0 career record in the Olympics, winning the gold medal in women's doubles every time they entered the event: in 2000, 2008 and 2012.
The American duo were seeded No 1 in Rio and coming off a 14th Grand Slam championship together at Wimbledon a month ago.
