Roger Federer and Rafael Nadal are professional tennis players engaged in a storied rivalry that many consider to be among the greatest in tennis history.

They have held the top two rankings on the ATP Tour since July 2005 and are the only pair of men to have ever finished four consecutive calendar years at the top. Federer was ranked No. 1 for a record 237 consecutive weeks beginning in February 2004. Nadal, who is five years younger, ascended to No. 2 in July 2005 and held this spot for a record 160 consecutive weeks before surpassing Federer in August 2008. Thus, Nadal is currently ranked No. 1 and Federer No. 2.

Nadal leads their overall head-to-head series 13–6. Because tournament seedings are based on rankings, 15 of their matches have been in tournament finals, including an all-time record seven Grand Slam finals. From 2006 to 2008, they played in everyFrench Open and Wimbledon final, and they also met in the 2009 Australian Openfinal. Nadal won five of the seven matches, losing only the first two Wimbledons. Three of these Grand Slam finals were five setters (2007 and 2008 Wimbledon, 2009 Australian), and the 2008 Wimbledon final has been lauded as the greatest match ever by many long-time tennis analysts. They have also played in a record seven Masters Series finals, including their five hour match at the 2006 Rome Masters.