Serena Williams is one of tennis’ biggest stars, and she’s anything but serene. Williams’ first major outburst on the court came in 2009, during a U.S. Open semifinal against Belgian Kim Clijsters. Williams was struggling to stay in the match when a line judge called a foot fault on her second serve, giving Clijsters two match points. Williams looks as if she was going to brush the call off and continue serving, but then turned suddenly and began yelling at the line judge, reportedly saying: “If I could, I would take this f—–g ball and shove it down your f—–g throat!” The line judge reported Williams to the match umpire, who gave her a point penalty because she already had one code violation from earlier in the match — breaking her racket at the end of the first set. That point penalty for “unsportsmanlike conduct” was the match point, which meant Clijsters won the game. At a press conference later, Williams, who was fined a record $82,500 for the offense, denied threatening the line judge. “I’ve never been in a fight in my whole life, so I don’t know why she would have felt threatened,” she said.