Naomi Osaka is making a major change at the start of the North American hard-court swing as the former world No. 1 decided to call time on her partnership with coach Patrick Mouratoglou.

Last week, the Japanese kicked off her summer on hard courts in Washington, where she defeated Yulia Putintseva in her opener before being bounced by Emma Raducanu in straight sets. Overall, the four-time Grand Slam champion is 21-12 this year and ranked at No. 49 in the world – a far cry from where she wants to be.

After failing to rediscover her old form, Osaka split with Wim Fissette following the conclusion of the 2024 US Open. The 27-year-old hired Mouratoglou shortly after. Now, less than a year of working together, they are separating. 

"Merci Patrick. It was such a great experience learning from you. Wishing you nothing but the best. You are one of the coolest people I've ever met and I'm sure I'll see you around," the four-time Grand Slam champion announced through an Instagram Story.

How Osaka's tenure with Mouratoglou went?

When Osaka hired Mouratoglou – who worked with Serena Williams for a decade and achieved massive success – she was hoping the French coach could lead her to the Promised Land. It didn't happen and their partnership is now a thing of the past.

When it comes to the Japanese's 2025 season, two results stand out – a runner-up finish in Auckland and her first clay title at the WTA 125 (Challenger) tournament in Saint-Malo. 

Now that Mouratoglou is gone, it will be interesting to see if Osaka brings someone to assist her or if she decides to go solo for some time. 

Today, the former world No. 1 is starting her campaign at the WTA 1000 tournament in Montreal, where she plays against world No. 515 Ariana Arseneault. The Japanese's form may not be the best but she enters as the major favorite against the 515th-ranked Canadian.