Naomi Osaka has lost in the third round of the Western and Southern Open after a three sets defeat to Switzerland’s Jil Teichmann.

The world number two had started the tournament well, beating Coco Gauff in the previous round, but made 41 unforced errors on her way to defeat in this contest.

This was only Osaka’s second competition since May, having taken some time away from the game to focus on her mental health. She made the third round at the Tokyo Olympics recently and is still some way from playing her best tennis.

Despite losing, the Japanese star revealed there are still positives for her to take ahead of the US Open at the end of the month, where Osaka will attempt to defend her title.

"I'm feeling more confident in myself,” she said. “There were times where I was doubting myself. It's important to remind myself what my strengths are. I think I did that well in the first set.

"In the second set, maybe I played a bit more to her rhythm, and also in the third set, as well."

The downside to this defeat is that Osaka can’t raise more money for the Haiti relief fund. The country was struck by a devastating earthquake last week and the 23-year-old has revealed she would donate all of her $24,000 (£17,800) winnings to helping the cause.

Naomi Osaka

Speaking in her press conference on Wednesday, Osaka admitted that the suffering going on in the world at the moment has put her own life into perspective. Before, she was “ungrateful” about her success, but now she appreciates her career a lot more.

“Seeing the state of the world, how everything is in Haiti and Afghanistan right now is definitely really crazy, and for me to just be hitting a tennis ball in the United States right now and have people come and watch me play is... I would want to be myself in this situation rather than anyone else in the world."

Meanwhile, Osaka’s rival Ashleigh Barty breezed into the last eight after beating Victoria Azarenka 6-0 6-2.

Jil Teichman faces fellow compatriot and Olympic champion Belinda Bencic in her quarter-final.