The 22-year-old Japanese joins similar protests by athletes in the National Basketball Association and Major League Baseball following the police shooting of Jacob Blake, a Black man, on Sunday (August 23) in Wisconsin.
“Before I am an athlete, I am a Black woman,” she said on Twitter.
“And as a Black woman I feel as though there are much more important matters at hand that need immediate attention, rather than watching me play tennis.”
Osaka defeated Anett Kontaveit 4-6 6-2 7-5 to reach the semis where she was scheduled to face Belgian Elise Mertens, who needed just over an hour to defeat qualifier Jessica Pegula 6-1 6-3 and reach her first Premier 5 semi-final.
By pulling out of the semi-finals Osaka is giving up the chance to sharpen her game further ahead of the August 31-September 13 U.S. Open Grand Slam but she said it was important for tennis to address the issue of racial injustice.