Federer and Nadal have been playing each other since 2004 and their rivalry is a significant part of both men's careers.[48][49][50][51][52]

They have held the top two rankings on the ATP Tour from July 2005 until 14 September 2009, when Nadal fell to World No. 3 (Andy Murray became the new No. 2). They are the only pair of men to have ever finished four consecutive calendar years at the top. Federer was ranked number 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.[53]

Nadal leads their head-to-head 13-7.[54] Because tournament seedings are based on rankings, 16 of their matches have been in tournament finals, including an all-time record 7 Grand Slam finals.[55] From 2006 to 2008 they played in every French Open and Wimbledon final, and then they met in the 2009 Australian Open final. Nadal won five of the seven, losing the first two Wimbledons. Three of these matches were five set-matches (2007 and 2008 Wimbledon, 2009 Australian Open), and the 2008 Wimbledon final has been lauded as the greatest match ever by many long-time tennis analysts.[56][57][58][59] They have also played in a record 8 Masters Series finals, including their lone five hour match at the 2006 Rome Masters which Nadal won in a fifth-set tiebreak.

Until 14 September 2009, when Juan Martin del Potro beat Nadal in the US Open semi-final on his way to defeating Federer in the final itself, no player had beaten Nadal and Federer in the same Grand Slam. Nadal has not lost a French Open (4) or Australian Open (1) final, while Federer was undefeated in US Open finals until losing to del Potro (5). Both have won Grand Slam events on three different surfaces successively (2008 French Open, 2008 Wimbledon, 2009 Australian Open for Nadal and 2008 US Open, 2009 French Open, 2009 Wimbledon for Federer).