Former world number one Naomi Osaka has parted ways with coach Wim Fissette.

It comes after she admitted to being frustrated with recent results following an early exit from the US Open last month.

The Japanese tennis star began working with the Belgian in 2020 and has had two stints with him.

Osaka, 26, won two of her four Grand Slams - the 2020 US Open and 2021 Australian Open titles - with Fissette in her corner.

"Four years, two Slams and a whole lot of memories. Thanks Wim for being a great coach and an even greater person. Wishing you all the best," Osaka wrote on Instagram.

Fissette rejoined Osaka when she returned to tennis in January following the birth of her daughter in July 2023.

However, Osaka has reached the quarter-finals in only two of the 16 tournaments she has played following her 15 months away, and has not gone past the second round of a Grand Slam.

"It's been a little difficult because obviously I can only gauge how I'm doing by results," she said after exiting the US Open last month.

"I feel faster. I feel better, but I lost in the second round. So it's a little rough.

"I feel like I'm working way harder than I've ever worked in my life, so it needs to turn into something."

Fissette has worked with Kim Clijsters, Simona Halep, Johanna Konta, Angelique Kerber, Victoria Azarenka and others in a celebrated coaching career.

In Fissette's mind, he and Osaka were on the verge of achieving something special in her comeback season.

"We were very close to a breakthrough," he wrote in an Instagram post.

"When you do the right things and keep hearing from peers you are in the right direction, it's tough not quite getting it yet. As the coach, you keep trusting the process, knowing the lessons are getting you closer to the trophies.

"After the US Open, Naomi decided to move forward with a new path. I accepted it knowing we close this second run with more good memories and gratitude for building her way back."