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

Naomi Osaka and coach Patrick Mouratoglou are done working together after less than a year, the four-time Grand Slam champion announced Sunday on social media. “Merci Patrick,” Osaka began her post, with a photo of her hitting a practice serve while he stands nearby.

Naomi Osaka is reportedly set to work with Tomasz Wiktorowski, the former coach of Iga Swiatek. The four-time Major winner announced her sudden split from Patrick Mouratoglou on Sunday, days after Emma Raducanu beat her in the second round of the WTA 500 in Washington.