Six months later, Bajin had guided Osaka into the top 20. And, within two years of benefiting from his tutelage, Osaka won her first major trophy, the 2018 US Open final where she outclassed Serena Williams in straight sets.
"Hey everyone, I will no longer be working together with Sascha," Osaka wrote on Twitter on Monday . "I thank him for his work and wish him all the best in the future."
Within an hour, Bajin said : "Thank you Naomi. I wish you nothing but the best as well. What a ride that was. Thank you for letting me be part of this."
Osakas decision took the sport by surprise
Bajin was the 2018 WTA Coach of the Year and had previously worked with Serena Williams, Victoria Azarenka, and Caroline Wozniacki.
Rothenberg even wrote that "the reasons for the split were unclear."
Neither Bajin, Osaka, or her agent Stuart Duguid have elaborated on what caused the split but it will likely be a hot topic in the weeks ahead.
The 21-year-old, currently without a coach, plays in the Dubai Tennis Championships in the United Arab Emirates on February 18. It is her first tournament since becoming the number one women's tennis player on the planet.
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