World number one Naomi Osaka has split with her coach Sascha Bajin 16 days after winning the Australian Open.
The Japanese 21-year-old, whose win in Melbourne sealed back-to-back Grand Slam titles, worked with the German for just over a year.
"I will no longer be working together with Sascha," Osaka tweeted. "I thank him for his work and wish him all the best in the future."
Bajin was named WTA coach of the year for 2018.
He is a former hitting partner of Grand Slam champions Serena Williams, Victoria Azarenka and Caroline Wozniacki.