Former world number one Naomi Osaka said she was close to rediscovering the form that brought her four Grand Slam titles, but acknowledged she had thought about retirement and often wondered how long she would continue playing.

The 29-year-old Japanese, who stepped away from tennis for 15 months after the birth of her daughter before coming back in 2024, returns to the Pan Pacific Open in Tokyo next week as the seventh seed.

"It's tough, sometimes I look towards my future and wonder how long I'm going to play," Osaka told reporters on Sunday.

"Because if my daughter did say she didn't want me to travel as much, I'm not the type of person to ignore that."

Currently ranked 19th in the world, Osaka has shown signs of returning to her best this season, reaching the quarter-finals at Wimbledon after beating top seed Aryna Sabalenka and making the last 16 at both the French Open and US Open.

She also reached the semi-finals in Washington and the quarter-finals in Toronto.

"I genuinely don't feel like I'm that far off," Osaka said of her chances of contending for titles again.

"I think I built a pretty solid base and I'm excited to see if I can continue learning and going further in tournaments."

Osaka opens her Tokyo campaign against Italy's Jasmine Paolini, while world number one Elena Rybakina also headlines the field alongside Alex Eala of the Philippines.