Isner–Mahut match at the 2010 Wimbledon Championships
The Isner–Mahut match at the 2010 Wimbledon Championships is the longest tennis match in history. It was a first-round men's singles match, in which the American 23rd seed John Isner played against French qualifier Nicolas Mahut.
Source: Wikipedia — Isner–Mahut match at the 2010 Wimbledon Championships (CC BY-SA 4.0)