Osaka's time with Mouratologou followed an up-and-down sequence of promising signs and frustrations with either injury or close-run defeats.

Osaka has won only one title while collaborating with Mouratoglou – more precisely the Saint-Malo WTA 125 – really too little for a champion of her caliber, who has made the recent history of women's tennis by becoming a point of reference for all her rivals.

The news comes after Naomi Osaka lost her second match at the D.C. Open and just before she begins competing in Toronto.