Naomi Osaka says she will head into her first-round match at the US Open against the former French Open champion Jelena Ostapenko, determined to compete with the confidence she has lacked in a difficult comeback season since giving birth to her daughter, Shai, in July last year.

“I made a promise to myself to be as confident as I can in the fact that I am who I am,” Osaka said. “Throughout the year I have had really hard matches, and it kind of dipped my confidence a little. I wouldn’t say that I played bad tennis. I just would say that I played really good players and I also learned a lot.”

After losing in the qualifying rounds of the Cincinnati Open just over a week ago, Osaka wrote a lengthy note on social media explaining how she has felt as if she has been in a different body since giving birth and everything about her game felt “almost brand new”. Her openness and vulnerability, particularly on a subject as common as returning to work postpartum, has resonated strongly with many people.

According to Osaka, her ballet movement and mental coach, Simone Elliott, has played a significant role in helping her to maintain her composure on the court. “In Cincinnati the day before my qualifying match, I was having a really hard time and an hour before the match I asked if I could talk to her,” she said. “We talked it through. Then obviously I was able to win the match and I felt pretty good after that.

“So you know me, I have had these moments where I have kind of had a breakdown on court. I feel if I didn’t talk to her, that possibly could have happened again in that moment. I’m really grateful for her. We do have journaling sessions. She’s actually the one who told me to get my little journal book that I read on court sometimes.”

Osaka says she has been feeling better after spending a significant amount of time on the practice court and training has gone well since Cincinnati. Voicing her feelings and concerns has been helpful: “It’s like speaking your words into the universe and letting them go,. After you [do] it, you’re kind of just free from the thoughts that muddle your mind.”