5. Mikhail Youzhny (2008)
Russian tennis star Youzhny never won a major, but he was a perennial contender. He was also famous for another, more bizarre reason. Whenever Youzhny made a serious mistake on the court, he reacted in a violent manner. However, this time his victim was himself. The Russian beat his own tennis racquet against his forehead. This eccentric behavior also cost him on multiple occasions.

First, at the Sony Ericsson Open in 2008, he drew blood when he gave himself a good whacking (via Sporting News). Later, he repeated the action at the French Open. This time, the impact caused a migraine and caused him to retire from his game. Another incident occurred in 2013 when he annihilated his racquet on the tennis court. Youzhny was a strange character but a compelling one.