The Nadal-Federer rivalry is perhaps the most legendary rivalry in tennis history as these two men have dominated the sport of tennis for the better part of a decade.
Here is a brief history of their colossal rivalry courtesy of Wikipedia:
Federer and Nadal have been playing each other since 2004, and their rivalry is a significant part of both men's careers.
They held the top two rankings on the ATP Tour from July 2005 until 14 August 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. Nadal ascended to No. 2 in July 2005 and held this spot for a record 160 consecutive weeks before surpassing Federer in August 2008.
They have played 28 times, and Nadal leads their head-to-head series 18–10 overall and 8–2 in Grand Slam tournaments. Fourteen of their matches have been on clay, which is statistically Nadal's best surface and statistically Federer's worst surface. Federer has a winning record on grass (2–1) and indoor hard courts (4–0) while Nadal leads the outdoor hard courts by 5–2 and clay by 12–2. Because tournament seedings are based on rankings, 19 of their matches have been in tournament finals, including an all-time record 8 Grand Slam tournament finals. From 2006 to 2008, they played in every French Open and Wimbledon final, and also met in the title match of the 2009 Australian Open and the 2011 French Open. Nadal won six of the eight, losing the first two Wimbledon finals. 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.
They have also played in a record 9 Masters Series finals.