Serena Williams Rio 2016 Olympics
Serena Williams is downcast as she loses a point to Elina Svitolina at the Rio OlympicsReuters

The No.1 seed in the men's draw exited in the first round, and now Novak Djokovic has been joined by the top seed of the women's singles – Serena Williams – in making an early exit from the tennis tournament of the Rio 2016 Olympics.

In tears as she struggled to cope with a shoulder injury, Serena was dumped out of the Olympics by Ukraine's Elina Svitolina 6-4, 6-3 in an hour and 12 minutes.

Serena, the reigning Olympic champion, had already seen her hopes of clinching a gold medal in the women's doubles go up in smoke after the Williams sisters – Serena and Venus – crashed out in the first round to Lucie Safarova and Barbara Strycova. Venus also lost in the first round in the women's singles, making it a truly forgettable Rio Olympics outing for the Williams family.

Rafael Nadal and Andy Murray had no problems, however, with both the players coming through their respective second round match unscathed.

Murray eased past Juan Monaco of Argentina 6-3, 6-1 in an hour and nine minutes, showing, yet again, why he is now the clear favourite for the men's gold medal. The defending champion, though, will need to remain at his best, because as the Djokovic and Serena results have showed, if you come up with anything short of a 100%, you will be in big trouble.

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If Nadal is at a 100% or not was the big question coming into the Rio Olympics, with the Spaniard withdrawing from the French Open early and then skipping Wimbledon to recover from a wrist injury.

Having come through the first couple of matches without too many issues, Nadal again showed signs of encouragement in his 6-3, 6-3 win over Italy's Andreas Seppi.

The 14-time Grand Slam champion would then later come out and win his men's doubles match with Marc Lopez, with the team from Spain beating the Austrian pairing of Oliver Marach and Alexander Peya 6-3, 6-1.