Serena Williams crashes out in the third round

Olympic champion and world number one Serena Williams tumbled out of the Rio de Janeiro singles competition in the third round on Tuesday after a shock defeat to Ukraine's Elina Svitolina. Spain's Garbine Muguruza also crashed out of the Olympics with a defeat to Monica Puig.

Serena Williams, the defending Olympic champion, lost in straight sets to Ukraine's Elina Svitolina.

Olympic champion and world number one Serena Williams tumbled out of the Rio de Janeiro singles competition in the third round on Tuesday after a shock defeat to Ukraine's Elina Svitolina.

Svitolina, ranked 20 in the world, stunned the London Games gold medallist 6-4, 6-3 to record a memorable victory against the American, who has won 22 grand slam singles titles.

In another major upset, Puerto Rico's Monica Puig collapsed in tears of joy after her shock 6-1, 6-1 win over Spain's French Open champion Garbine Muguruza on Tuesday. Puig, ranked 34, downed world number three Muguruza in just over an hour and will play Germany's Laura Siegemund in the quarterfinals of the Olympic tennis tournament.

Russia's Evgeny Donskoy edged out Spain's world number 12 David Ferrer in three tense sets. Donskoy, ranked 84 in the world, put out former French Open finalist Ferrer 3-6, 7-6(1), 7-5.

“In important moments he played more aggressively than me," said 34-year-old Ferrer, who conceded this may be his last Olympics.

The highest seeds remaining in the men's tournament, Andy Murray and Rafael Nadal, progressed into the third round with ease. Murray, who won singles gold at the London Games, outclassed Monaco 6-3, 6-1 and will next face either France's Benoit Paire or Italy's Fabio Fognini.

'Good match'

“I played pretty well, hit the ball good from the back of the court, not many unforced errors. It was a good match,” said Murray, who is the favourite to defend his title after Serbian world number one Novak Djokovic was eliminated in the first round.

The 2008 Olympic gold medallist Nadal overpowered Italy's Seppi Andreas 6-3, 6-3 despite admitting over the weekend that he was still not fully fit. His Spanish compatriot Carla Suarez Navarro was less fortunate. World number nine Madison Keys outlasted her 6-3, 3-6, 6-3 to reach the last eight.

Keys struggled to find her rhythm but in the end her powerful strokes proved too much for Suarez Navarro, who has one of the best one-handed backhands in women's tennis.

“It was a really tough match,” said Keys, who will now face Russia's Daria Kasatkina.