Serena Williams got on Twitter Tuesday evening to call out the tennis industry of discriminating against her. She says the “random” drug tests happen more in tennis than in any other sport.

“It’s that time of day to get ‘randomly’ drug tested and only test Serena,” she said. “Out of all the players it’s been proven I’m the one getting tested the most. Discrimination? I think so. At least I’ll be keeping the sport clean.”

She then added, “But I’m ready to do whatever it takes to have a clean sport so bring it on. I’m excited.”

But I’m ready to do whatever it takes to have a clean sport so bring it on. I’m excited.

— Serena Williams (@serenawilliams) July 25, 2018

…and it’s that time of the day to get “randomly” drug tested and only test Serena. Out of all the players it’s been proven I’m the one getting tested the most. Discrimination? I think so. At least I’ll be keeping the sport clean #StayPositive

— Serena Williams (@serenawilliams) July 25, 2018

Serena has won 23 Grand Slam championships, making her the “Greatest Athlete of All Time.”