Serena Williams' ex-coach Rick Macci has credited Naomi Osaka for making the right coaching change and rediscovering her form. The former World No. 1 recently chalked up a semifinal run in New York.Osaka entered the American hard-court swing after three wins and three losses on grass. After a second-round exit in Washington, she secured a runner-up finish in Montreal and reached the semifinals in New York.Macci highlighted how decision-making can play a key role on tour. He hinted that the four-time Grand Slam champion avoided disaster by quickly changing her coach."Change is very important when your struggling and you have as much talent as anybody on tour. One action can improve your on court reaction. Osaka got a new focused accurate voice and Right Away on court you saw a better choice. She got smarter quicker and faster played free and avoided disaster. The mind is a muscle that you need to Train and now Naomi is winning with her skill set and Brain," Serena Williams ex-coach Rick Macci saidOsaka started her partnership with Patrick Mouratoglou in September 2024. The duo secured a runner-up finish in Auckland and clinched the title in Saint-Malo (ITF) during their 10-month stint on tour.The four-time Grand Slam champion parted ways with Mouratoglou in July. She thanked him for his efforts and wished him the best in his future endeavours."It was such a great experience learning from you. Wishing you nothing but the best. You're one of the coolest people I've ever met, and I'm sure I'll see you around," Naomi Osaka saidThe Japanese pro has now joined forces with Iga Swiatek's ex-coach Tomasz Wiktorowski. The exact date of their partnership is unknown, but the duo have been spotted training together since the Canadian Open in July.Osaka spoke about her coaching change and how Wiktorowski creates a safe working environment for her."He seemed like such a tough guy to me, but actually, when he smiles, he really is like a teddy bear. When we talk after matches, he's not harsh at all. He's, like, always very proud and encouraging. I feel like it kind of creates a safe space for me to be able to express myself and my tennis," Naomi Osaka saidIn less than two months, the latest duo have already secured a runner-up finish in Montreal. They were also one win away from entering the US Open final, but Amanda Anisimova defeated Osaka in New York.“I'm happy that I lost in the semis instead of the first round" - Naomi Osaka shares her feeling after a promising run at the US OpenNaomi Osaka at the 2025 US Open - Day 12 - Source: GettyNaomi Osaka is a two-time champion at the US Open. Despite missing out on a spot in the final, she felt satisfied with her performance this time around.Here's what Osaka said in her post-match press conference after the semifinal:“I'm happy that I lost in the semis instead of the first round or the third round or whatever I usually get to I don't feel sad. It's really weird. Well, it's not weird, because I just feel like I did the best that I could,” Naomi Osaka said.The 27-year-old defeated the likes of Coco Gauff and Karolina Muchova in the second week of the US Open. She only dropped one set en route to the semifinals this year.“Honestly, it's kind of inspiring for me because it makes me just want to train and try to get better, and hopefully just give it my very best shot again and see what happens. But I think I can't be mad or upset at myself,” she addedOsaka could be seen in action at the Japan Open on tour. She is a two-time finalist at the event (2016 and 2018).