Tennis is still a sport for white people, many feel uncomfortable watching Black and Asian players practicing hard: Naomi Osaka's mother Tamaki

Tennis star Naomi Osaka has become an icon and role model for youngsters, not just because of her success on the court, but her fight for justice off it too. Her mother, Tamaki Osaka, believes that there is still work to be done for tennis to be more racially just and inclusive.

Tamaki Osaka penned down her thoughts on various things in a recently-published book in Japanese. The title of the book translates in English to "Through the Tunnel: Just One More Day, My Days of Chasing a Reckless Dream."

Speaking in a recent interview, Osaka said that she and her daughters, Naomi and Mari, faced certain challenges as they tried to practice tennis in the US, coming from a different background and ethnicity.

"Tennis is still a sport for the white community. There must be many people who feel uncomfortable watching Black people and Asians practicing tennis hard," Naomi Osaka's mother expressed.

The 24-year-old tennis superstar herself has not mentioned any specific events or challenges she and Mari faced while growing up. However, Naomi has been a huge advocate for racial justice over the last few years, often lending her time and effort to the Black Lives Matter movement.

At the 2020 US Open, she wore different masks during each of her matches, to pay tribute to black victims of police brutality.

In the book, Tamaki also reflected on the struggles the Osaka family faced a few years ago. That included her working multiple shifts and getting hardly three hours of sleep at night, right up to the time Naomi started playing on the WTA tour.

"I had no money, worked nonstop and cried all the time," she mentions in her book.

Now that Naomi Osaka has achieved a lot at such a young age and has attained superstar status in the sport, her mother has a special message in her book.

"I wanted to convey a message to young women in my book," and wants her daughters to "think for themselves and do whatever they want."

The rise of Naomi Osaka - the world's highest-earning female athlete

Osaka in action at the 2022 French Open

For another year running, Naomi Osaka reigned supreme as the highest-earning female athlete in the world. With earnings of $53.2 million, including prize money as well as endorsements and sponsorships, Osaka is also 20th on the list of highest-earning athletes in the world (male and female).

The young star pipped her idol growing up, Serena Williams, who is the second-highest earning female athlete.

Naomi Osaka first made headlines at the age of 16, when she defeated Samantha Stosur on her WTA main draw debut at the 2014 Stanford Classic. Despite certain ups and downs, Osaka continued to rise up the ranks over the next few years.

Shortly before her 21st birthday in 2018, Osaka won her maiden US Open title, defeating Serena Williams in the final. She has four Grand Slam titles to her name (two titles each at the US Open and Australian Open).