Question: Roger Federer and Rafael Nadal competed in tennis competitions against each other in what came to be known as what rivalry?

<P0-S0> The 2008 Rafael Nadal tennis season officially began on January 1 with the start of the 2008 ATP Tour. <P0-S1>  Nadal's 2008 tennis season is considered to be one of his best seasons on tour. <P0-S2>  Nadal won 8 titles in 2008, including two Grand Slams and the Olympic Gold medal. <P0-S3>  In addition, Nadal also won three Masters titles - Monte Carlo, Rome and Toronto. <P0-S4>  Nadal's winning streak of 32 in 2008 is the longest across three surfaces in tennis history. <P0-S5>  He won the French Open for the loss of no sets and just 41 games, in one of the most comprehensive Grand Slam performances of all time. <P0-S6>  Nadal also won Wimbledon that year, defeating Roger Federer in what is widely recognized as the greatest tennis match in history. <P0-S7>  He won the Olympic Gold medal at Beijing, becoming the first ever top-5 player to win the Gold medal in the Open Era. <P0-S8>  Nadal also claimed the No. 1 ranking that year after the Olympics. <P0-S9>  He finally ascended to the top spot after 160 consecutive weeks as No. 2. <P0-S10>  Nadal would hold the No. 1 ranking for the rest of the season and finish the year ranked No. 1 for the first time in his career. <SEP> <P1-S0> The 2017 Australian Open Men's Singles final was the championship tennis match of the Men's Singles tournament at the 2017 Australian Open. <P1-S1>  It was contested between Roger Federer and Rafael Nadal, ranked 17th and 9th in the world respectively. <P1-S2>  It was their record ninth meeting in a Grand Slam final in their rivalry, and their 1st meeting in a Grand Slam final since the 2011 French Open. <P1-S3>  In a rematch of the 2009 Australian Open final, which Nadal won in 5 sets, Roger Federer won the duel in 5 sets, beating Nadal for the first time in a Grand Slam since the 2007 Wimbledon final. <P1-S4>  He also trailed Nadal 3–1 in the final set but won 5 games in a row to win the title. <P1-S5>  This ended a 6-match losing streak against Nadal in Grand Slam events. <P1-S6>  Having lost all of their previous three encounters, this was the first time Federer defeated Nadal at the Australian Open and also marked Federer's first Grand Slam victory over Nadal outside the grass courts of Wimbledon. <P1-S7>  Federer extended his record of Grand Slam men's singles titles to 18, marking the third time he broke his own all-time record, after breaking the previous record of 14, held by Pete Sampras. <SEP> <P2-S0> The Federer–Nadal rivalry (known colloquially as Fedal) is between two professional tennis players, Roger Federer of Switzerland and Rafael Nadal of Spain. <P2-S1>  They are engaged in a storied rivalry, which many consider to be the greatest in tennis history. <SEP> <P3-S0> The Djokovic–Nadal rivalry is between tennis players Novak Djokovic and Rafael Nadal, who are engaged in a modern-day tennis rivalry. <P3-S1>  The rivalry is the most prolific of the Open Era. <P3-S2>  The two have faced each other 50 times with Djokovic leading 26–24. <P3-S3>  Between 2006–2010, this rivalry was often overshadowed by the historic Federer–Nadal rivalry, but it started to become widely recognized after they played their first Grand Slam final against each other at the 2010 US Open. <P3-S4>  The first half of the rivalry was dominated by Nadal (who led 16–7 after the 2010 season) while the second half has been dominated by Djokovic, winning 11 out the last 13 matches. <P3-S5>  It is widely considered to be one of the greatest rivalries in tennis history. <P3-S6>  It was the first rivalry to involve meetings at all 4 Grand Slam finals (including four consecutive Grand Slam finals) and a record 26 Masters Series matches. <P3-S7>  Their 2012 Australian Open final is considered to be one of the greatest matches of all time, and Mary Carillo and John McEnroe both commented that that Australian Open match and the 2013 French Open semi-final match were the two best matches played on hard and clay courts respectively. <P3-S8>  The Djokovic–Nadal rivalry was listed as the third greatest rivalry in the last decade in 2009 by "ATPworldtour.com" despite its only starting in 2006.