The longest recorded tennis match lasted 11 hours - Apparently.
In 2010, John Isner of the United States and Nicolas Mahut of France played a Wimbledon match that lasted a staggering 11 hours and 5 minutes. The match, which was played on June 22-24, consisted of 183 games and 3 sets. The marathon match was eventually won by Isner 6-4, 3-6, 6-7, 7-6, 70-68, with the final set taking 8 hours and 55 minutes to complete.