Defending Gold medal champion Serena Williams has been bundled out of the Rio Olympics by Ukrainian Elina Svitolina.

Williams lost her third round match 6-4, 6-3, after earlier in the week losing the first round in the doubles with sister Venus.

Meanwhile, Australian Sam Stosur is also out after a straight sets loss to Australian Open champion Angelique Kerber.

The world No.2ย advanced to the fourth round with a 6-0, 7-5 win over the Aussie to end her medal hopes in the singles compeition a clinical performance.

Kerber will face Great Britain's Johanna Konta in the quarterfinals.

However, she is still a chance to win a medalย for her country in doubles, with Stosur and John Peers set to take onย Indian pairย Sania Mirza and Rohan Bopanna in the firstย round of the mixed doubles.