USA's Serena Williams (R) and USA's Venus Williams react after losing a point during their women's first round doubles tennis match against Czech Republic's Lucie Safarova and Czech Republic's Barbora Strycova at the Olympic Tennis Centre of the Rio 2016 Olympic Games in Rio de Janeiro on August 7, 2016. / AFP / Martin BERNETTI (Photo credit should read MARTIN BERNETTI/AFP/Getty Images)
