Question: Roger Federer and Rafael Nadal competed in tennis competitions against each other in what came to be known as what rivalry?
Context: Roger Federer won two Majors in 2009, the French Open, defeating Robin Söderling in the final, and the Wimbledon Championships with a victory over Andy Roddick.  In addition, Federer made two other Grand Slam finals, Australian Open losing to Rafael Nadal, and the US Open, losing to Juan Martín del Potro.  Federer went on to win two other Master Series 1000 tournaments: in Madrid over Rafael Nadal, and in Cincinnati over Novak Djokovic.  He lost in one 500 level event final in Basel to Djokovic.  During the year, Federer completed the Career Grand Slam by winning his first French Open title, and won a record fifteenth Grand Slam singles title, one more than Pete Sampras' mark of fourteen. The 2017 Australian Open Men's Singles final was the championship tennis match of the Men's Singles tournament at the 2017 Australian Open.  It was contested between Roger Federer and Rafael Nadal, ranked 17th and 9th in the world respectively.  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.  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.  He also trailed Nadal 3–1 in the final set but won 5 games in a row to win the title.  This ended a 6-match losing streak against Nadal in Grand Slam events.  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.  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. The Federer–Nadal rivalry (known colloquially as Fedal) is between two professional tennis players, Roger Federer of Switzerland and Rafael Nadal of Spain.  They are engaged in a storied rivalry, which many consider to be the greatest in tennis history. Roger Federer won one slam in 2008, which came at the 2008 US Open, defeating Briton Andy Murray, 6–2, 7–5, 6–2.  Federer was defeated by Rafael Nadal in two Grand Slam finals: at the 2008 French Open, which he lost 1–6, 3–6, 0–6, and at the 2008 Wimbledon Championships in a five-setter, 4–6, 4–6, 7–6, 7–6, 7–9, when he was going for six straight wins to break Björn Borg's record.  At the 2008 Australian Open, Federer lost in the semifinals to Novak Djokovic, ending his record of 10 consecutive Major finals.  Roger Federer lost twice in Master Series 1000 Finals on clay to Nadal at Monte Carlo and Hamburg.  However, Federer was able to capture three more victories in 250-level events at Estoril, Halle, and Basel. The 2012 Roger Federer tennis season officially began on 2 January with the start of the 2012 ATP World Tour.  Federer began the year with a semifinals finish at the Australian Open after a four-set loss to archrival Rafael Nadal.  He recovered from his loss with three consecutive titles at the ABN AMRO World Tennis Tournament, the Dubai Duty Free Tennis Championships, and the BNP Paribas Open.  He won his fourth title at the Mutua Madrid Open on blue clay, becoming the only person to win a title on blue clay in ATP history.  By doing so, he regained the #2 ranking from Rafael Nadal At the French Open, Federer played four tough matches before he was ousted by Djokovic in the semifinals. On 24 August 2016, Roger Federer and Rafael Nadal were the first of six players to confirm their participation for team Europe.  On 15 May 2017, more than eight months later, Milos Raonic was the first of six players to confirm his participation for the World team.  By 24 August 2017, all six players from each team had been chosen: Roger Federer, Rafael Nadal, Alexander Zverev, Marin Čilić, Dominic Thiem, and Tomáš Berdych for team Europe, and Milos Raonic, John Isner, Jack Sock, Sam Querrey, Juan Martín del Potro, and Denis Shapovalov for team World.  Shortly afterwards Raonic withdrew and was replaced by Nick Kyrgios.  Later Frances Tiafoe took the place of del Potro who had also withdrawn. The 2008 Rafael Nadal tennis season officially began on January 1 with the start of the 2008 ATP Tour.  Nadal's 2008 tennis season is considered to be one of his best seasons on tour.  Nadal won 8 titles in 2008, including two Grand Slams and the Olympic Gold medal.  In addition, Nadal also won three Masters titles - Monte Carlo, Rome and Toronto.  Nadal's winning streak of 32 in 2008 is the longest across three surfaces in tennis history.  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.  Nadal also won Wimbledon that year, defeating Roger Federer in what is widely recognized as the greatest tennis match in history.  He won the Olympic Gold medal at Beijing, becoming the first ever top-5 player to win the Gold medal in the Open Era.  Nadal also claimed the No. 1 ranking that year after the Olympics.  He finally ascended to the top spot after 160 consecutive weeks as No. 2.  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. The 2009 Australian Open Men's Singles final was the championship tennis match of the Men's Singles tournament at the 2009 Australian Open.  It was contested between the world's top two players for much of the previous four years, Rafael Nadal and Roger Federer, then ranked first and second in the world respectively.  It was their seventh (out of nine) meeting in a Grand Slam final, but their first outside of either the French Open or Wimbledon, followed by their most recent meeting at the final of the 2017 Australian Open.  This was Rafael Nadal's first Grand Slam hard court final while it was Roger Federer's ninth and at the time he was yet to lose in a Grand Slam hard court final. Roger Federer reached all four Grand Slam finals in 2006, winning three of them.  His only Grand Slam loss came against Rafael Nadal in the French Open final in four sets, 6–1, 1–6, 4–6, 6–7(4).  This was the first time they had met in a Major final.  In the other three Grand Slams of 2006, Federer defeated Nadal in the final of the Wimbledon Championships, 6–0, 7–6(5), 6–7(2), 6–3.  He defeated Marcos Baghdatis, 5–7, 7–5, 6–0, 6–2, at the Australian Open and Andy Roddick, 6–2, 4–6, 7–5, 6–1, at the US Open.  In addition, Federer made it to six ATP Masters Series 1000 finals, winning four on hard surfaces and losing two on clay to Nadal.  Also, Federer won one ATP 500 series event in Tokyo, three ATP 250 series events in Doha, Halle, and Basel, and captured the Year-End Championships for the third time in his career.  In December 2011, Stephen Tignor, chief editorial writer for Tennis.com, ranked Federer's 2006 season as the second greatest season of all-time during the open era; behind only Rod Laver's Calendar Grand Slam year of 1969. The Djokovic–Nadal rivalry is between tennis players Novak Djokovic and Rafael Nadal, who are engaged in a modern-day tennis rivalry.  The rivalry is the most prolific of the Open Era.  The two have faced each other 50 times with Djokovic leading 26–24.  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.  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.  It is widely considered to be one of the greatest rivalries in tennis history.  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.  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.  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.
Answer: Federer–Nadal rivalry