18. Serena Williams
Naomi Osaka won her first Grand Slam title in 2018 when she defeated Williams in the U.S Open. However, Williams’ behavior throughout the game tarnished the win for the Japanese-Haitian athlete. She received three violations throughout the game and ended it by calling the umpire a ‘thief.’ Meanwhile, Williams’ fans booed Osaka after she won her first major title.
It was so bad that Osaka felt obliged to apologize after the game. “I know that everyone was cheering for [Williams], and I’m sorry it had to end like this,” she said. After, Williams acknowledged that she was in the wrong and that Osaka was a worthy winner. She apologized to her opponent and instructed the crowd to give her respect. However, her antics on the court were pathetic at the time.