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Naomi Osaka knocked out of Tokyo Olympics in shocking upset

No. 2 ranked Osaka lost in the third round to Marketa Vondrousova of the Czech Republic.
Image: Tennis - Olympics: Day 4
Naomi Osaka and Marketa Vondrousova. The Czech player beat Osaka 6-1, 6-4 in the third round Tuesday. David Ramos / Getty Images

Days after lighting the Olympic cauldron to get the Games underway, Naomi Osaka was eliminated from the Tokyo Olympics.

The No. 2 ranked tennis player in the world was knocked out of the tennis tournament in the third round Tuesday by Marketa Vondrousova of the Czech Republic, 6-1, 6-4.

Osaka beat China's Zheng Saisai in the first round and Switzerland's Viktorija Golubic in the second round.

Osaka on Tuesday was down four games in less than 15 minutes. The four-time Grand Slam champion then won her first service game but ended up losing the set 6-1 in just 24 minutes.

Image: Tennis - Women's Singles - Round 3
Marketa Vondrousova of Czech Republic shakes hands with Naomi Osaka of Japan after their third round match.Piroschka Van De Wouw / Reuters

During a long rally at the top of the second set, Osaka quickly broke serve to win two straight games. The match then became a roller coaster as Vondrousova battled back to even the score, and the opponents began trading games while holding serve. Throughout the match, Osaka stood far behind the baseline and missed a number of the Czech's signature drop shots.

Up 5-4 in the second, Vondrousova managed to break Osaka's serve one more time — and win the match.

After the match, organizers said that Osaka left the venue and would not be talking to the media, the Associated Press reported.

But she returned briefly and was asked about whether her recent break from tennis or the hot, humid weather factored into Tuesday's outcome.

"I would say that everyone played in the same conditions, so it didn’t really matter that much," Osaka said.

Osaka, 23, returned to the court for the Olympics after a two-month mental-health break.

She withdrew from the French Open in May and did not compete at Wimbledon.

In quitting the French Open, she cited anxiety and said she did not want to do media interviews at that event, saying that she said she wanted to prioritize her mental health.

Image: Tennis - Women's Singles - Round 3
Osaka, who was competing for Japan, returned to the court for the Olympics after a two-month break from the sport. Piroschka Van De Wouw / Reuters

Osaka also said that she "suffered long bouts of depression" since being catapulted into the national spotlight after a controversial victory over Serena Williams in the U.S. Open of 2018.

"The best thing for the tournament, the other players and my well-being is that I withdraw so that everyone can get back to focusing on the tennis going on in Paris," she said in May. "I never wanted to be a distraction and accept that my timing was not ideal and my message could have been clearer."

Osaka said before the Tokyo Games that she felt recharged by the break, and she hoped the attention to it let others know that it is OK to talk about mental health issues.

"I just had to believe in myself from the beginning," Vondrousova said after Tuesday's victory. Vondrousova is a former French Open finalist. "I felt really good from the beginning."

Osaka was born in Japan but came to the United States as a child and was raised in America and was a dual citizen. She gave up her U.S. citizenship and is playing for Japan. Under Japanese law, dual citizens are required to make a “declaration of choice,” renouncing one of their citizenships before their 22nd birthday.

Osaka's loss was the second upset of a top-ranked player in the Tokyo Olympics.

Ashleigh Barty of Australia, the No. 1 ranked player, was ousted in the first round to Spain's Sara Sorribes Tormo.

This story originally appeared on NBCNews.com.