Naomi Osaka was upset in the third round of the Tokyo Olympics, losing to Marketa Vondrousova, of the Czech Republic, in straight sets on Tuesday.

The second-ranked Japanese tennis star lost 6-1, 6-4 to the former French Open finalist. She said after the match she was starting to feel some of the pressure as being one of the faces for the Games. Osaka lit the Olympic cauldron and is one of the highest-paid female athletes in the world.

CLICK HERE FOR MORE SPORTS COVERAGE ON foxnews.1eye.us

"I definitely feel like there was a lot of pressure for this. I think it’s maybe because I haven’t played in the Olympics before and for the first year (it) was a bit much," Osaka said, adding that there was probably a ton of pressure on her opponent as well.

Osaka met with a small group of reporters after initially deciding not to comment after the loss.]

The Olympics had been her first tournament since she took a mental health break from tennis. She dropped out of the French Open in May and skipped Wimbledon to prepare for the Games.

ALASKA'S LYDIA JACOBY SHOCKS WITH OLYMPIC SWIM GOLD

"I’ve taken long breaks before and I’ve managed to do well. I’m not saying that I did bad right now, but I do know that my expectations were a lot higher," she said.

"I feel like my attitude wasn’t that great because I don’t really know how to cope with that pressure so that’s the best that I could have done in this situation."

Vondrousova won four straight games to start the matchup. Osaka would break Vondrousova’s serve in the opening game of the second set but almost immediately handed the break back when she double-faulted to make it 2-2.

Osaka had two break points to take a 4-3 lead in the second but the Czech star hit consecutive drop shots to win and get back into the game.

CLICK HERE TO GET THE FOX NEWS APP

"I just really believed the second I stepped on the court," she said.

Vondrousova will face off against Spain’s Paula Badosa Gibert in the quarterfinals.

The Associated Press contributed to this report.