Naomi Osaka is targeting a fifth grand slam win of her career, so says Patrick Mouratoglou.

Osaka, who has won the Australian Open twice and the US Open twice, will head into 2025 as the world number 59.

The former world number one has had a stop-start career in recent years, as she took time away from the sport to focus on her mental health, before then giving birth.

She has taken part in 18 WTA Tour-level competitions this season, with her best effort a run to the quarter-finals at the Qatar Open in February.

Mouratoglou, a former coach of Serena Williams, has been helping to guide the 27-year-old, and he explained Osaka has set her sights on another major crown.

"[With] Serena, motivation was extremely key after she beat the record of [Martina] Navratilova and Chris Evert [to reach 23 Grand Slam singles titles]," he told Sky Sports.

"But I think we worked so well together because I think we were both motivating each other all the time. I knew exactly how to talk to her. She knew exactly how to talk to me. I was pushing her, she was pushing me and that was like that every day.

"So that's why it works so well. For Naomi, it's different because she really feels she has to give and do much more. She had two very difficult years.

"First, she had this mental health issue, and then she had a baby. So she's been out, and then she restarted the year this season and it was not a very good season.

"Before the first tournament we did together she was 80 in the world and she knows she can do much better than that.

"She's extremely motivated to come back and win grand slams, and it's a pleasure for me because that's the dream of every coach: to have a player who has that level of motivation."