Who said tennis isn't a blood sport? Russian Mikhail Youzhny used his racquet to fix his inner game during his 3rd round match at the 2008 Sony Ericsson Open. Youzhny was trailing Spain's Nicolas Almagro 5-4 in the 3rd set. He went on to win in a tiebreaker.
When you can't think straight on the court, straighten your frontal lobe.