The seemingly unpredictable nature of the Olympic tennis tournaments in Rio threw up another surprise on Tuesday as women’s world number one Serena Williams crashed out.

The American lost 6-4 6-3 to Ukraine’s Elina Svitolina, with Williams apparently troubled by a shoulder problem during the third-round match.

The Williams sister, Serena and Venus, are the most successful in Olympic tennis history with four gold medals each but Rio has offered them little.

Venus lost in the opening round of the singles to Kirsten Flipkens while the sisters lost an Olympic doubles match for the first time ever on Sunday.

The exit of 22-time Grand Slam champion Serena means Angelique Kerber (Germany) and Madison Keys (USA) are the only top-eight seeds remaining in what had appeared a very strong field.

Despite battling back from 3-1 down in the second set to level at 3-3 during a mini-recovery, Williams dropped her service once more courtesy of a remarkable five double faults in one game.

The 34-year-old saved a pair of match points before ultimately coming undone when she drove a forehand wide.

Williams had pulled out of a tournament in Montreal two weeks prior to the Olympics with a shoulder problem and it appears that has resurfaced.

Afterwards Williams was, as always, magnanimous in defeat. “The better player today won but I can’t wait for next time and I know next time is going to be a really good match and I look forward to it,” she said. “It was a great opportunity.

It didn’t work out the way I wanted it to but at least I was able to make it to Rio – that was one of my goals.”

Svitolina is 2.50 to win her next match against Petra Kvitova of the Czech Republic, who is 1.50 to progress from the round four clash.