Serena Williams lost the U.S. Open to Naomi Osaka on Saturday after clashing with an umpire who penalized her, calling him a “a thief,” and complaining she was treated differently than male tennis players. Williams racked up three violations over the course of the second set, growing angrier with each one. The first was for coaching–umpire Carlos Ramos ruled that a hand-gesture by her coach violated the rules–and came with a warning. “I don't cheat to win,” Williams protested to Ramos. The second was for smashing her racket, and she was penalized one point. She erupted, calling Ramos a “thief,” and was then given a one-game penalty for verbal abuse. After Osaka won, 6-2, 6-4, Williams continued to stand up to Ramos. “You owe me an apology!” she said. According to the New York Times, Williams then complained she was being treated unfairly, saying, “There are men out here that do a lot worse, but because I’m a woman, because I’m a woman you’re going to take this away from me?” The drama overshadowed the victory by Osaka, who became the first woman from Japan to win a Grand Slam singles title. Both players were tearful during the trophy ceremony but Williams also defended her protest. The Associated Press reported that when Williams was asked what she would tell her baby daughter about the match, she said: “I’ll tell her, first of all, if she sees it, that, you know, I stood up for what I believed in. I stood up for what was right."