<p>Japan's four-time Grand Slam winner Naomi Osaka is back on the tennis court for practice and has hinted that she is likely to return to action at next year's Australian Open.</p>.<p>Naomi, who left the tennis court after making a tearful exit from the US Open two months ago declaring she was taking a break due to mental health issues, announced her return to training in posts on the social media that included photographs of her on a court in a foreign location with a racquet in her hand and wearing work-out apparel.</p>.<p>"Kinda rusty but feels good to be back," Osaka tweeted with the photos. "Good to be back. I really want to say thank you, everyone, for all the kind messages, I really appreciate it," she added.</p>.<p>Her social media posts have no hint of when and where she might return.</p>.<p>The posts reflected her mood which was in quite a contrast to her emotions in September in New York when she revealed unhappiness and mental issues, following her loss to Canadian teen Leylah Fernandez.</p>.<p>Osaka has not played a WTA event since losing in the US Open.</p>.<p>World No. 13 Osaka celebrated her 24th birthday during a vacation in Greece last month. She is the reigning champion at the Australian Open, which is set to start in Melbourne on January 17.</p>.<p><strong>Check out DH's latest videos:</strong></p>
<p>Japan's four-time Grand Slam winner Naomi Osaka is back on the tennis court for practice and has hinted that she is likely to return to action at next year's Australian Open.</p>.<p>Naomi, who left the tennis court after making a tearful exit from the US Open two months ago declaring she was taking a break due to mental health issues, announced her return to training in posts on the social media that included photographs of her on a court in a foreign location with a racquet in her hand and wearing work-out apparel.</p>.<p>"Kinda rusty but feels good to be back," Osaka tweeted with the photos. "Good to be back. I really want to say thank you, everyone, for all the kind messages, I really appreciate it," she added.</p>.<p>Her social media posts have no hint of when and where she might return.</p>.<p>The posts reflected her mood which was in quite a contrast to her emotions in September in New York when she revealed unhappiness and mental issues, following her loss to Canadian teen Leylah Fernandez.</p>.<p>Osaka has not played a WTA event since losing in the US Open.</p>.<p>World No. 13 Osaka celebrated her 24th birthday during a vacation in Greece last month. She is the reigning champion at the Australian Open, which is set to start in Melbourne on January 17.</p>.<p><strong>Check out DH's latest videos:</strong></p>