Osaka and Bajin joined hands in December 2017, subsequently, the Japanese went high up the hill on the WTA ladder.
" Thanks to my team, I don't think I would have made it through this week without you".
Osaka shared an unexpected tweet and announced her decision to end the duo's time together. What a ride that was. "Thank you for letting me be part of this".
Already seemed destined to be intertwined with Serena's, the fledgling but fruitful career of Osaka's again overlaps with the 37-year-old American's in that Bajin is also a former coach of Serena's.
Osaka withdrew from this week's Qatar Open, citing a back injury.
By winning a second grand slam and becoming world No 1, she firmly established herself as at the forefront of the next generation of women players.
She was born in Japan - her mother is Japanese, her father is Haitian - and moved to the United States when she was 3.