Column: Serena Williams eliminated from Olympic tennis tournament

Not until the crowd at the Olympic Tennis Centre roared in shock and Serena Williams approached the net to concede did Elina Svitolina allow herself to believe she had beaten the defending Olympic champion and 22-time Grand Slam tournament winner Tuesday.

The 21-year-old from Ukraine never assumed she would prevail over the world’s No. 1 player, even though her chances improved dramatically when Williams double-faulted five times in the seventh game of the second set. “It happens sometimes with her game and her serve and she can also do four aces in a row, so you need to expect [the] unexpected,” Svitolina said. “I was staying in the moment.”

The moment and the match were hers a few minutes later, when she wrapped up a 6-4, 6-3 third-round victory that moved her into the quarterfinals and sent Williams home without a medal. For Svitolina, who is ranked No. 20 in the world and had won only one set in four previous matches against Williams, it was a magical night. “For me, the Olympics is the most,” she said.

For Williams, who committed 37 unforced errors, it was another stunning loss in Rio. She and her sister Venus, who won doubles gold at London in 2012 and were the top-seeded duo here, lost in the first round, their first-ever Olympic doubles defeat. This Olympic tournament has been cruel to No. 1 seeds: Novak Djokovic was eliminated in the first round, as was the French doubles duo of Nicolas Mahut and Pierre-Hugues Herbert.

Williams’ progressively more erratic serve — she double-faulted seven times in the second set and eight times overall — and her difficulty on overheads were indications she might have been hampered by a shoulder injury, although she didn’t mention it among the few remarks she made in response to questions from Tom LaDue, an executive of the U.S. Tennis Assn. She had cited an inflamed shoulder when she withdrew from the Rogers Cup tournament in Montreal last month and clearly labored here.

Frustration during the first set of her second-round match against Alize Cornet had driven her to smash her racquet on a bench, but she recovered to win that match in straight sets. She couldn’t push back hard enough against Svitolina on Tuesday after breaking Svitolina’s serve to pull even at 3-3 in the second set.

“Obviously, I’m disappointed, but she played really well and I think the better player today won,” Williams said in a heavily raspy voice. “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.”

Playing in the Olympics, she said, “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, who has been working with former No. 1 player Justine Henin, said she “got the feeling” Williams might have been hurting but was more concerned about herself. “I was trying to stop thinking about it and just stay in the moment and play the ball. Don’t play against Serena Williams, Olympic champion and so many Grand Slams. Just play the ball,” Svitolina said.

Svitolina was smart and in control, committing only 17 unforced errors. She converted five of nine break points, including in the third, seventh and final games of the second set. The secret to her success, she said, was simple.

“Being in the moment. That’s definitely what helped me today,” she said. “Just relax and go for my shots because I was doing some winners, especially in the second set when it was really tight.”

But the magnitude of her victory didn’t set in until Williams’ final shot sailed wide. “It felt just an unreal feeling,” said Svitolina, who will next face No. 2 seed Petra Kvitova of the Czech Republic.

Williams, who had planned her Olympic return since she triumphed in London, was left with memories but no hardware this time. Playing with Venus, she said, “was awesome. It was fun. It’s over now.”

So, too, is her chance of defending her singles title, and a lot sooner than anyone expected.

helene.elliott@latimes.com

Twitter: @helenenothelen