World number one Naomi Osaka says she was not willing to "sacrifice" her happiness following her surprise split from coach Sascha Bajin last week.
Osaka split with Bajin 16 days after winning the Australian Open, which sealed back-to-back major titles after she won her first at the 2018 US Open.
"Everyone thinks it was a money-related issue, but it wasn't," said Osaka.
"I wouldn't put success over my happiness. I'm not going to sacrifice that just to keep a person around.
"That's one of the most hurtful things I've ever heard."
Japan's Osaka, 21, had worked with Bajin for just over a year when she announced the split on Twitter.