World number one Naomi Osaka has split from her coach Sascha Bajin just weeks after winning the Australian Open to complete back-to-back grand slam victories, the Japanese player said on Monday.
"Hey everyone, I will no longer be working together with Sascha. I thank him for his work and wish him all the best in the future," the 21-year-old tweeted in a shock announcement.
Osaka, who became the first Asian to hold the top ranking after beating Czech Petra Kvitova in the Melbourne final, had worked with the German for just over a year.
No reason was given for the decision to part ways.
The Japanese player captured her first slam by stunning Serena Williams at last year's US Open in a final remembered as much for the American's astonishing rant at the chair umpire following a coaching violation.