NEW YORK -- Last year at the US Open, Naomi Osaka was sitting with her mother in the stands on Arthur Ashe Stadium as a spectator. The two-time US Open champion had just given birth to her daughter, Shai, over the summer, and she was beginning to turn her eye toward a return to competition. 

As she watched a then 19-year-old Gauff scurry around the court en route to her first major title, Osaka couldn't help but wonder: Could she really do this again? 

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"I do remember when I was watching Coco's match last time I was here," Osaka said Sunday at US Open Media Day, "I felt very inspired to play again. At that time, I didn't know at what level could I play.

"So I think when I got to Australia earlier this year and when I played the French Open, honestly I'm a little shocked sometimes at how well the play is. Obviously I want to be in the Top 10, and I want to do all these things, but I still, in the back of my mind, remember not being able to run or not being able to do a sit-up."

On Tuesday, Osaka will play her first US Open match since 2022. After starting the season unranked, the former No.1 has played a nonstop schedule to put herself back in the Top 100, at No.88 on the PIF WTA Rankings.

In the most high-profile first-round match of the tournament, Osaka will face 2017 French Open champion and World No.10 Jelena Ostapenko. It will be their first match in over eight years. Osaka won their sole meeting at the 2016 French Open in straight sets. A year later, Ostapenko was a Grand Slam champion at 20 years old. A year after that, Osaka stunned the field in New York to win her first of four major titles.

"I think it's going to be really fun," Osaka said. "She's honestly one of my favorite players to watch. I think we are polar opposites in a way.

"I respect her a lot. She was the first player in our generation to win a Grand Slam. She's a champion."

After a disappointing summer, which included second-round losses at the National Bank Open and Cincinnati Open, Osaka posted a heartfelt message to her fans on social media

"My biggest issue currently isn’t losses though, my biggest issue is that I don’t feel like I’m in my body,” Osaka wrote. "It’s a strange feeling, missing balls I shouldn’t miss, 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 through.

"Internally, I hear myself screaming, '[W]hat the hell is happening?!?!'"

It wasn't the first time Osaka has offered a confessional status update on social media and it won't be the last. Expressing her insecurities publicly has helped lessen the emotional load, especially before big tournaments. That openness has been helped along by her mental coach, Simone Elliott, who is also her movement coach. 

A former ballerina, Elliott is a full-time traveling member of Osaka's team, which includes coach Wim Fissette and performance coach Florian Zitzelsberger, who is Elliott's husband. 

"I remember in Cincinnati the day before my qualifying match, I was having a really hard time," Osaka said. "An hour before the match I asked if I could talk to her. We talked it through. Then obviously I was able to win the match, and I felt pretty good after that.

"I have had these moments where I have kind of had a breakdown on court. I feel like if I didn't talk to her, that possibly could have happened again in that moment. So I'm really grateful for her."

Elliott is the one who encouraged Osaka to begin keeping a journal and to feel free to use it during matches. 

"[The work we do] is kind of more casual, but I think it's just 'cause she knows that's the type of person I am."

From the start of the season, Osaka has been open about her focus on the fall hard-court season. Her heavy tournament schedule was designed to build towards the US Open and the Asian swing. That extra motivation might make all the difference over the next weeks. 

"I was watching in the stands last year, and I promised myself this is going to be the tournament where I do the best," Osaka said. "Or hopefully here or Japan or during the Asian swing. That's kind of where I put all my energy.

"I guess we'll see what happens."

Watch this: Naomi Osaka and Iga Swiatek's 1st match at 2019 Toronto