John Robert Isner is an American professional tennis player and is considered to be one of the greatest servers the game has ever seen. He achieved his career high singles ranking of World No. 9 in April 2012, and is currently the highest ranked male American tennis player at World No. 11, as of June 2014. In 2013, he became the 18th player to serve more than 5000 aces on the ATP World Tour. He currently has 16th most aces in the history of ATP, having served more than 5500 aces.At the 2010 Wimbledon Championships, he played the longest professional tennis match in history, defeating Nicolas Mahut in a total of 11 hours and 5 minutes of play over the course of three days.