Grunting is allowed in tennis. Mock grunting is, apparently, not. Dutch player Robin Haase found that out the hard way during an ATP Challenger Tour event in the Czech Republic. Each time opponent Gonzalo Lama hit the ball during one particular rally, he made a loud grunt. Haase, silent for a few turns, then let out a grunt of his own, per CBS Sports.
The official then called Haase for "hindrance" and gave the point to Lama—though Haase passionately argued the decision. Lama went on to win the match in straight sets. Haase may simply be missing his coach, who was arrested in Amsterdam in March in connection with a millionaire businessman's murder, notes the Telegraph. (Read more tennis stories.)