This was never the way it was supposed to go for Naomi Osaka, the biggest new star in tennis, whose fame, reach and success appeared to have no limits at the start of the year.

Since then, Osaka has experienced a series of setbacks and losses so overwhelming that she said after the latest one, on Friday night at the US Open, that she did not know when she would play her next tennis match.

Osaka lost in three tight and unusually temperamental sets to a rising, unseeded 18-year-old Canadian named Leylah Fernandez 5-7, 7-6 (2), 6-4 in the third round of the Open that Osaka won a year ago.

Then, in her post-match news conference, she began to tear up, giving the world another troubling portrait of the state of mind of a woman who would appear to have everything — money, fame, glamour, the admiration of millions of fans on multiple continents.

“How do I go around saying this,” Osaka began, choking back tears. “I feel like for me recently, when I win I don’t feel happy, I feel more like a relief. And then when I lose I feel very sad. And I don’t think that’s normal.

“This is very hard to articulate,” she continued after collecting herself. “Well, basically. I feel like I’m kind of at this point where I’m trying to figure out what I want to do, and I honestly don’t know when I’m going to play my next tennis match.”

The prospect of Osaka stepping away from the sport indefinitely will undoubtedly send shockwaves through the tennis-sphere.

The daughter of a Japanese mother and a Haitian father who is a citizen of her native Japan, though she was raised largely in the US, Osaka is the world’s highest-paid female athlete.