Naomi Osaka admits she still feels out of sorts on the court eight months into her comeback season after maternity leave, struggling with a puzzling lack of power and precision.

The four-time Grand Slam champion faced another setback in her inconsistent return, losing to Ashlyn Krueger in the second round of qualifying for the Cincinnati Open.

This latest defeat comes as she prepares for the U.S. Open, the final Grand Slam of the year, from Aug. 26 to Sept. 8.

"My biggest issue currently isn't losses; my biggest issue is that I don't feel like I'm in my body," Osaka wrote on Instagram on Tuesday.

"It's a strange feeling, missing balls I shouldn't miss and hitting balls softer than I remember I used to. I try to tell myself, 'It's fine, you're doing great. Just get through this one and keep pushing.' Mentally, it's really draining."

"Internally, I hear myself screaming, 'What the hell is happening?!'"

Osaka returned to action in January after a 15-month break during which she gave birth to her daughter. Now ranked 90th in the world, her best results have been runs to the quarterfinals at Doha and 's-Hertogenbosch.

"I've played a handful of matches this year where I felt like myself, and I know this moment is probably just a small phase from all the new transitions (clay, grass, clay, hard). However, the only feeling I could liken how I feel right now to is being postpartum," Osaka said.

"That scares me because I've been playing tennis since I was three; the racket should feel like an extension of my hand."

Osaka's next event will be at Flushing Meadows, where she triumphed in 2018 and 2020, but she said she does not understand why everything about her game feels "almost brand new" again.

"This should be as simple as breathing to me, but it's not," she added. "I genuinely did not give myself grace for that fact until just now."

Despite her struggles, Osaka said she loves putting in the work each day and "eventually having the opportunity to get to where you want to be."