Women's Quarter Finals - Pat Rafter Arena, Brisbane, Australia, January 3, 2019 Japan's Naomi Osaka with coach Sascha Bajin before her match against Latvia's Anastasija Sevastova.
Australian Open Champion Naomi Osaka has announced a surprising split with coach Sascha Bajin to abruptly end their momentous 13-month partnership.
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.
She also thanked Bajin and wished him "all the best in the future". "Thank you for letting me be part of this", he responded to Osaka's tweet.
Under Bajin, Osaka rose from world number 72 at the start of the 2018 to the summit of the rankings little over a year later.
In their second tournament together, Osaka produced her career best result at a Grand Slam event.