Former world No. 1 Naomi Osaka has announced that she’s no longer working with coach Wim Fissette. Osaka had expressed frustration with her recent results after a second-round exit at the U.S. Open just over two weeks ago. The 26-year-old Osaka won two of her four Grand Slam titles while working with the Belgian coach. Those were the 2020 U.S. Open and the 2021 Australian Open. It’s the second time Osaka and Fissette have parted ways. On her Instagram story late Friday, the Japanese player wrote: “4 years, 2 Slams and a whole lot of memories. Thanks Wim for being a great coach and an even greater person, wishing you all the best.” She’s currently ranked No. 75. Fissette began working with Osaka shortly before the start of the 2020 season. They had split in the summer of 2022 before teaming up again last year when Osaka returned to training following maternity leave. “In 15 years on tour, this was one of my best years working together with amazing people,” Fissette wrote in an Instagram …