John Robert Isner (born April 26, 1985) is an American professional tennis player. Considered one of the best servers of the ATP World Tour, Isner achieved his career-high singles ranking of world No. 9 in April 2012. In 2013, he became the 18th player to serve more than 5,000 aces on the ATP World Tour. He currently has 10th-most aces in the history of ATP, having served more than 7,300 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. He also played the then 10th-longest singles match, a 5-hour 41-minute encounter in the second round of the 2012 French Open.