Never heard of Lucy Diggs Slowe, now after reading about her, she's legit, both as a tennis legend, but more importantly as an educator..
She even excelled in education more than on the tennis court. Plus, an activist on behalf of her people which is bold given the era we're talking about.

She was also brave enough not to hide her sexual preference - a solid lesbian and proud of it, especially that time!
Strangely enough, I knew of two of her famous lovers: Mary Burrill/playwright & Angelina Grimke/poet - she banged the shit out of both of them - but never heard of Lucy Slowe.

One more thing, Serena was a great tennis player but unlike Lucy Slowe & Althea Gibson, she wasn't an activist on behalf of her people. Actually Serena has become an embarrassment with her deep self-hatred..
Can someone tell Serena to STOP BLEACHING THE SHIT OUT OF HER BLACK SKIN? She already got rid of her African nose, so please Serena, STOP! Dammmnitttt