Serena and Venus Williams lost for the first time in an Olympics doubles match as their hopes of winning a fourth successive title were surprisingly ended in the first round at Rio 2016.
The American top seeds lost 6-3 6-4 to Czech Republic's Lucie Safarova and Barbora Strycova, who were only paired together at late notice.
Strycova replaced Karolina Pliskova, who withdrew because of Zika concerns.
It was the Williams' first defeat in 16 Olympic matches playing together.
The sisters won gold together at Sydney 2000, Beijing 2008 and London 2012, but did not compete at Athens 2004 after Serena pulled out through injury.