Serena Williams is not having a great Summer Olympics.

In another Olympic shocker, she was ousted from the singles tournament on Tuesday.

The tennis sensation and defending gold medalist fell to Elina Svitolina of the Ukraine, 6-4, 6-3, in the women's singles round of 16. It was a performance full of errors for Williams, who had many mistakes and double-faults throughout the match.

Williams' run in the Summer Games in Rio de Janeiro has come to an end surprisingly early, leaving the tennis star to have to acknowledge her early exit after the loss.

"Obviously I'm disappointed," Williams told USA Today Sports "The better player won. It was a great opportunity that didn't work out the way I wanted it to. At least I was able to make Rio, which was one of my goals. It was awesome, but it's over now."

It's been a rough Summer Olympics for Williams as she and her sister Venus fell in the first-round of the doubles tournament, so she's no longer in that bracket either.

Williams had previously dominated Svitolina in the French Open, defeating her 6-1, 6-1 on June 1 to advance to the quarterfinals before eventually falling to Garbine Muguruza in the finals of the tournament. The Ukraine native was the No. 20 seed in that tournament.

This year marks the first time that Williams will leave the Olympics empty-handed. She won the gold medal in the singles and doubles competitions at the 2012 London Games.

Williams has dealt with many injuries as of late, but it's uncertain if they had anything to do with her struggles. The soon-to-be 35-year-old also didn't seem comfortable with the conditions of the hard courts.

It was an all around ugly performance for Williams, who had 35 unforced errors and double-faulted five times.

For Svitolina, it was a victory she won't soon forget.

"It was just an unreal feeling, just a relief for me because I didn't expect even in that moment that I could win," Svitolina said. "And I think it helped me a lot -- you don't expect mistakes from her and just fight and stay focused. Being in the moment, that's definitely what helped me today, and just relax and go for my shots because I was doing some winners and especially on the second set when it was really, really tight."

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