World No. 1 Naomi Osaka announced on social media Thursday that Jermaine Jenkins, who was recently hired as the United States Tennis Association national coach for women's tennis, has joined her team as her new coach.

Jenkins, 34, served as Venus Williams' hitting partner until recently. Osaka's former coach Sascha Bajin, with whom she abruptly parted ways earlier this month, used to be hitting partner of Venus' younger sister Serena Williams.

(Naomi Osaka's new coach Jermaine Jenkins, far left)[Screenshot from Osaka's Instragram post]

"Had a great dinner with the team. Also taking this moment to thank Jermaine for joining us and coming on board," Osaka said on Twitter.

The 21-year-old Osaka split from Bajin just two weeks after winning the Australian Open to secure her second straight Grand Slam title, moving her to the top of the WTA rankings for the first time.

Osaka lost her first match since becoming world No. 1 when she was knocked out in the second round of the Dubai Tennis Championships by Kristina Mladenovic last week.

She will next attempt to defend her title at the upcoming BNP Paribas Open in Indian Wells, where she won her first WTA singles crown last year.