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.
Bajin, the 2018 WTA coach of the year, is a former hitting partner of Grand Slam champions Serena Williams, Victoria Azarenka and Caroline Wozniacki.
Under him, Osaka rose from world number 72 at the start of 2018 to the summit of the rankings little over a year later.
No reason was given for the split at the time, but Osaka says issues with the German had been “brewing” at January’s Australian Open.
“I think some people could see that, if they saw how we interacted,” she told reporters at the WTA event in Dubai.
“I’m not going to say anything bad about him because, of course, I’m really grateful for all the things he’s done.
“During the Australian Open, I was just trying to tell myself to get through it. I’m not sure, but I think you guys noticed.”
Osaka said she hopes to have a new coach in place by the BNP Paribas Open in Indian Wells, which starts on 4 March.
“[The most important thing for me is] just to have a positive mindset,” Osaka added. “I don’t want someone that’s in the box saying negative stuff. That would be the worst.
“[I want] someone that’s kind of direct, not afraid to say things to my face. I’d rather someone say it directly to me than go around my back. That’s one of the biggest things.”