The former world number one is appearing at the Pan Pacific Open for the first time in four years, and she came onto the court wearing a blue robe with long kimono-like sleeves.

She said the crane pattern was a nod to her mother's home in the northern island of Hokkaido and that the occasion "felt like a homecoming."

"It felt like on the fashion side I was always giving these great moments to the Slams, and I felt like coming home, I wanted to do something special here too," the four-time Grand Slam winner said.

Osaka is known for grabbing headlines with her eye-catching, custom-made outfits.

She channeled NBA fashion trailblazer Allen Iverson at the US Open and wore an audacious "jellyfish-inspired" outfit in Australia.

Osaka also drew on her Japanese heritage with a kimono-inspired white dress at Wimbledon.

She said her latest Tokyo outfit was made by the same designer.

Asked if she planned to unveil more outfits this week, she replied: "It would be fun if you watch it and then be surprised."

Osaka's last appearance at the tournament in 2022 ended with her pulling out with abdominal pain before her second-round match.

She has since become a mother, taking 15 months away from the sport after the birth of her daughter Shai before returning in 2023.

The 29-year-old, who is now ranked 18 in the world, said she had "changed a lot" since her last appearance in Tokyo.

"In that period of my life I was not panicked but stressed all the time," she said.

"Now I'm pretty calm, and I do think that has to do with my daughter."

"She balances me up and it's made me understand that this is my job."

Osaka had a tough opening assignment against world number 35 Paolini, who won their only previous encounter.

Osaka's power and accuracy were too much for the Italian in the first set, but the second was a much closer affair.

Osaka said she was "pretty confident going into the tiebreaker" after hitting seven aces in the match.