### Instruction: Which season was Roger Federer's most important in his career?
### Input: Federer played his first junior match in 1996 at the age of 14 at a grade 2 tournament in Switzerland. His main accomplishments as a junior player came at Wimbledon in 1998 when he won both the boys' singles final over Irakli Labadze, and in doubles teamed with Olivier Rochus defeating the team of Michaël Llodra and Andy Ram. In addition he reached the US Open Junior final in 1998, losing to David Nalbandian. Federer won four ITF junior singles tournaments in his career, including the prestigious Orange Bowl, where he defeated Guillermo Coria in the final. By the end of 1998 he attained the No. 1 junior world ranking and was awarded ITF junior World Champion. He ended his junior career at the end of 1998 with a high-ranking of No. 1 in singles and No. 7 in doubles (both attained on December 31, 1998) and a win–loss record of 78–20 in singles and 36–21 in doubles.

Junior Grand Slam results – Singles:

Australian Open: SF (1998)
French Open: 1R (1998)
Wimbledon: W (1998)
US Open: F (1998)

Junior Grand Slam results – Doubles:

Australian Open: SF (1998)
French Open: 1R (1998)
Wimbledon: W (1998)
US Open: 1R (1998)

1998–2002: Early professional career
Main article: Roger Federer's early career
Federer made his ATP debut at the 1998 Swiss Open Gstaad in his home country of Switzerland losing to Lucas Arnold Ker in the first round. Later that year, he won his first ATP match in Toulouse against Guillaume Raoux. He got a wildcard into the 1998 Swiss Indoors and lost in the first round to 4th seed and former world number 1 Andre Agassi. Federer finished his career as a 10-time champion of the tournament.

Federer entered the top 100 ranking for the first time on 20 September 1999 and started at the 1999 Marseille Open defeating the reigning champion of the 1998 French Open, Spaniard Carlos Moyá. His first final came at the Marseille Open in 2000, where he lost to fellow Swiss Marc Rosset. Federer won the 2001 Hopman Cup representing Switzerland, along with world No. 1 Martina Hingis. The duo defeated the American pair of Monica Seles and Jan-Michael Gambill in the finals. Federer later said that his experience with Hingis "definitely helped me to become the player I am today."

Federer's first singles win was at the 2001 Milan Indoor tournament, where he defeated Julien Boutter in the final. Although he won his first title already in 1999 on the Challenger tour, winning the doubles event in Segovia, Spain with Dutchman Sander Groen, the final was played on Federer's 18th birthday. In 2001, Federer made his first Grand Slam quarterfinal at the French Open, losing to former world No. 2 and eventual finalist Àlex Corretja. His run to the French quarterfinals launched him into the top 15 for the first time in his career.

His international breakthrough came at the 2001 Wimbledon Championships, when the 19-year-old Federer faced the four-time defending champion and all-time Grand Slam leader Pete Sampras. Federer beat the No. 1 seed in a five-set match to reach the quarterfinals. In the quarters he faced Englishman Tim Henman, eventually losing in a fourth-set tiebreaker.

The first final he reached at the Masters level came at the 2002 Miami Masters event, where he lost to former and future No. 1 Andre Agassi on hard court. Federer won his first Master Series event at the 2002 Hamburg Masters on clay, over Marat Safin; the victory put him in the top 10 for the first time. Federer made 10 singles finals between 1998 and 2002, of which he won four and lost six. He also made six finals in doubles. He finished 2001 with an ATP ranking of No. 13, and 2002 was the first year he was ranked within the top 10, finishing at No. 6.

2003: Grand Slam breakthrough at Wimbledon
Main article: 2003 Roger Federer tennis season
In 2003, Federer won his first Grand Slam singles title at Wimbledon, beating Andy Roddick in the semifinals and Mark Philippoussis in the final. In August he had a chance to take over the No. 1 ranking for the first time from Andre Agassi if he made it to the Montreal final. However, he fell in the semifinals to Roddick, in a final-set tiebreaker, leaving him 120 points behind Agassi. This, coupled with early losses to David Nalbandian at Cincinnati and the US Open, denied Federer the chance to become No. 1 for the duration of the season.

Federer won his first and only doubles Masters event in Miami with Max Mirnyi and made it to one singles Masters event in Rome on clay, which he lost. Federer made it to nine finals on the ATP Tour and won seven of them, including the 500 series events at Dubai and Vienna. Lastly, Federer won the year-end championships over Andre Agassi, finishing the year as world No. 2, narrowly behind Andy Roddick by only 160 points.

2004: Imposing dominance
Main article: 2004 Roger Federer tennis season
During 2004 Federer won three Grand Slam singles titles and became the first person to do in one season so since Mats Wilander in 1988. His first major hard-court title came at the Australian Open over Marat Safin, making him the world No. 1 for the first time. He then won his second Wimbledon crown over Andy Roddick. At the US Open, Federer defeated the 2001 champion, Lleyton Hewitt, for his first title there.

Federer won three ATP Masters events, one on clay in Hamburg, and the other two on hard surfaces at Indian Wells and in Canada. Federer took the ATP 500 series event at Dubai and wrapped up the year by winning the year-end championships for the second time. He also won his first tournament on home soil by capturing the Swiss Open in Gstaad. His 11 singles titles were the most of any player in two decades, and his record of 74–6 was the best since Ivan Lendl in 1986. He reached the year-end No. 1 ranking for the first time.

2005: Consolidating dominance
Main article: 2005 Roger Federer tennis season
In 2005, Federer failed to reach the finals of the first two Grand Slam tournaments, losing the Australian Open semifinal to eventual champion Safin after holding match points, and the French Open semifinal to eventual champion Rafael Nadal. However, Federer reestablished his dominance on grass, winning Wimbledon for a third time by defeating Andy Roddick. At the US Open, Federer defeated Andre Agassi in the latter's last major final.

Federer also took four Masters wins: Indian Wells, Miami and Cincinnati on hard court, and Hamburg on clay. The win in Miami was particularly noteworthy as it was the first final contested between Federer and Nadal. Federer recovered from two sets and a break down to take the final in five sets. Furthermore, Federer won two ATP 500 series events at Rotterdam and Dubai. Federer lost the year-end championships to David Nalbandian in five sets while playing through a foot injury that sidelined him for almost the rest of the season after September. He maintained his position as No. 1 for the entire season.

Federer won 11 singles titles, which ties his 2004 season. Federer's 81 match victories were the most since Pete Sampras in 1993, and his record of 81–4 (95.2%) remains the third-best winning percentage in the Open Era behind John McEnroe's 1984 and Jimmy Connors's 1974.

2006: Career-best season
Main article: 2006 Roger Federer tennis season
The 2006 season was statistically the best season of Federer's career. In November 2011, Stephen Tignor, chief editorial writer for Tennis.com, ranked Federer's 2006 season as statistically the second-best season of all time during the Open Era, behind Rod Laver's Grand Slam year of 1969.


Federer hits a forehand at the 2006 US Open, where he became the first man in history to achieve the Wimbledon-US Open double for three consecutive seasons.
Federer won 12 singles titles (the most of any player since Thomas Muster in 1995 and John McEnroe in 1984) and had a match record of 92–5 (the most wins since Ivan Lendl in 1982). Federer reached the finals in an astounding 16 of the 17 tournaments he entered during the season.

In 2006, Federer won three Grand Slam singles titles and reached the final of the other, with the only loss coming against Nadal in the French Open. This was Federer and Nadal's first meeting in a Grand Slam final. He was the first man to reach all four finals in a calendar year since Rod Laver in 1969. Federer defeated Nadal in the Wimbledon Championships final. In the Australian Open, Federer defeated Marcos Baghdatis, and at the US Open, Federer defeated 2003 champion Roddick. In addition, Federer reached six Masters finals, winning four on hard surfaces and losing two on clay to Nadal. Federer, however, consistently pushed Nadal to the limit on clay throughout the season taking him to fourth-set tiebreakers in Monte-Carlo and Paris, and a thrilling match in Rome that went to a deciding fifth-set tiebreaker.

Federer won one ATP 500 series event in Tokyo and captured the year-end championships for the third time in his career, again finishing the year as world No. 1. Federer only lost to two players during 2006, to Nadal four times in finals, and to 19-year-old Andy Murray in the second round of the 2006 Cincinnati Masters, in what was Federer's only defeat before the final of a tournament that year. Federer finished the season on a 29-match winning streak, as well as winning 48 of his last 49 matches after the French Open.

Near the end of the season he won his hometown tournament, the Swiss Indoors in Basel, Switzerland for the first time, having finished runner up in 2000 and 2001, and missing the tournament in 2004 and 2005 due to injuries.

2007: Holding off young rivals
Main article: 2007 Roger Federer tennis season
In 2007, Federer reached all four Grand Slam singles finals, winning three of them again. He won the Australian Open without dropping a set, beating Fernando González in the final. This made him the first man in the 21st century to accomplish the feat, as Björn Borg at the 1980 French Open was the last to win a Grand Slam tournament without the loss of a set. Federer had entered the year on a huge winning streak and after capturing his fourth Dubai crown Federer's winning streak stood at 41 matches, the longest of his career and only five shy of the record. Federer entered Indian Wells as the three-time defending champion, but his streak ended in controversy. He was defeated by an Argentine, Guillermo Cañas, who had failed a drug test for illegal doping.


Federer was called "Darth Federer" by fans and commentators at the 2007 US Open.
This surprising first-round loss marked the first time he was defeated since August 2006, a period spanning over 7 months.

During the clay season Federer's victory in the Hamburg Masters final was particularly impressive, as it snapped Nadal's 81-match winning streak on clay, an Open-era record. Federer turned the match around from a set down to sweep 12 of the final 14 games, including a final set bagel. At the French Open, some anticipated that Federer could become the first man in almost 40 years to hold all four majors simultaneously, having just resoundingly defeated young rival Nadal on clay entering the tournament. However, in a repeat of the previous year Federer played a tough four-set final against Nadal, but was undone by going 1/17 on break-point chances.

At Wimbledon Federer entered the tournament not only as the four-time defending champion, but also riding a 48-match winning streak on grass. Once again, he defeated Rafael Nadal for a second consecutive year in the final, this time in a thrilling five-set encounter that many analysts hailed as the greatest Wimbledon final since 1980. Victory at Wimbledon equaled him with Björn Borg for the record of five consecutive championships at the All England Club.

Federer reached the final in Montreal before playing a young and relatively unknown Serbian named Novak Djokovic. Djokovic proved his potential by beating the world No. 1 in a final-set tiebreaker upset. Federer rebounded in Cincinnati to capture his fifth title of the year. Federer entered the US Open as the three-time defending champion and faced Djokovic in the final. This time, Federer prevailed in a close straight-set match. Victory in New York moved him ahead of Laver and Borg for third on the all-time list of major championship victories. Throughout the tournament the American press nicknamed him Darth Federer for his all-black attire (which included tuxedo-striped shorts) and the tournament played "The Imperial March" from Star Wars when he was announced onto the court for each of his matches. He closed out the year with victories in Basel and the year-end championships in Shanghai.

He finished the season as the year-end No. 1 for the fourth year in a row, demonstrating his dominance, and during these four years he won 11 Grand Slam singles titles. After his phenomenal triple Grand Slam season yet again, Federer became the only player in history to win three majors in a year for three years (2004, 2006, 2007). It was the third consecutive season that Federer held the No. 1 ranking for all 52 weeks of the year.

2008: Illness, Olympic Gold, and fifth US Open
Main article: 2008 Roger Federer tennis season
Federer's success in 2008 was severely hampered by a lingering bout of mononucleosis, which he suffered during the first half of the year. At the end of the year he suffered a back injury.

In 2008, Federer captured one Grand Slam, a singles title at the US Open over Andy Murray. Federer was defeated by Nadal in two Grand Slam finals, the French Open and Wimbledon, which was regarded as the best match of tennis history by many, when he was going for six straight wins to break Björn Borg's record. He came back from two sets down to force a fifth set, where he fell just two points from the title. At the Australian Open Federer lost in the semifinals to eventual winner Djokovic, which ended his record of 10 consecutive finals. He lost twice in Masters finals on clay to Nadal, at Monte Carlo and Hamburg. Federer captured three titles playing in 250-level events at Estoril, Halle, and Basel.

At the Olympic Games Federer and Stan Wawrinka won the gold medal in doubles, after beating the Bryan brothers American team in the semifinals and the Swedish duo of Simon Aspelin and Thomas Johansson in the final. However, Federer could reach only the quarterfinals in the singles draw, bowing out to then No. 8 James Blake, ceding his No. 1 ranking to Nadal after being at the top for a record 237 consecutive weeks. He ended the year ranked No. 2.

Federer entered the 2009 season with 13 Grand Slams, only one behind Pete Sampras' all-time record. The season began with a loss to Nadal in the final of the Australian Open in a hotly contested five-set match. Federer struggled following the defeat in Melbourne and entered the clay season without a title.


Federer winning the 2009 French Open, and completing the career Grand Slam
Federer's season turned around in the final Masters event of the clay season when he defeated Nadal on clay for only the second time to capture the Madrid Masters. Federer entered the French Open with few predicting him to win the elusive Parisian title having lost to Nadal in the final weekend for the past four seasons. After Nadal's unexpected defeat to Robin Söderling, Federer became the overwhelming favorite. In his next match, he came from two sets and break point down in the third set to defeat Tommy Haas in five sets. He also fought back from a two-sets-to-one deficit against a young Juan Martín del Potro to win a five setter in the semifinals. In the final, he faced Söderling, and with straight sets victory, he finally captured the Coupe des Mousquetaires and career Grand Slam. This victory also tied him with Pete Sampras for the most Grand Slam singles titles.

Federer turned his sights to the grass courts of Wimbledon, where he breezed his way up to the final. In the championship match he faced long-time rival Andy Roddick in what was their eighth and final meeting at a Grand Slam. Roddick pushed Federer into a record-setting fifth set, which Federer claimed 16–14 to win his 15th Grand Slam singles title, breaking the all-time record of Pete Sampras.

Federer continued his summer run by winning his third title on the lightning-fast courts of the Cincinnati Masters, defeating Novak Djokovic in the final. At the US Open he defeated Söderling in the quarters and Djokovic, for the third consecutive year, in the semifinals. On the penultimate point of the Djokovic match he hit what many consider to be the greatest shot of his career, a tweener winner, to set up match points. Federer was defeated by del Potro in the final despite leading two sets to one and falling just two points from the title in the fourth set.

The 2009 season was perhaps the most historically relevant of Federer's career as he completed a career Grand Slam by winning his first French Open title and won a men's record fifteenth Grand Slam singles title at Wimbledon, surpassing Pete Sampras's mark of fourteen. The Wimbledon final was also historic for being the longest Grand Slam final in terms of games played with Federer prevailing 16–14 in the fifth set.

Federer finished the season as the year-end No. 1 for the fifth time in his career.

2010: Fourth Australian Open
Main article: 2010 Roger Federer tennis season

Federer won a record 16th major at the 2010 Australian Open.
Federer started the year with a win at the Australian Open, where he defeated Andy Murray in the final, extending the Grand Slam singles record to sixteen titles and matching Andre Agassi's record of four Australian Open titles. Since Wimbledon 2005 Federer had made 18 out of 19 finals in Grand Slam tournaments, a period of sustained excellence unparalleled in the Open Era. This tournament, however, marked the end of his dominance at the majors.

At the French Open, Federer won his 700th tour match and 150th tour match on clay. However, he failed to reach a Grand Slam semifinal for the first time since the 2004 French Open, losing to Söderling in the last 8 and relinquishing his No. 1 ranking, having been just one week away from equaling Pete Sampras's record of 286 weeks as world No. 1. In a huge upset at Wimbledon, Federer lost in the last 8 again to Tomáš Berdych and fell to No. 3 in the rankings for the first time in 6 years and 8 months.

Towards the middle of July, Federer hired Pete Sampras' old coach Paul Annacone on a trial basis to put his tennis game and career back on track. At the 2010 US Open Federer reached the semifinals, where he lost a five-set match to Novak Djokovic after holding two match points. Federer made it to four Masters finals prevailing against Mardy Fish at the Cincinnati Masters.

Federer finished the year in strong form, winning indoor titles at the Stockholm Open, Swiss Indoors, and the ATP Finals in London bringing his tally to 66 career titles. Federer won the year-end championships in London by beating rival Rafael Nadal for his fifth title at the event. He beat all contenders except Nadal in straight sets. It remains the only tournament in his career where Federer defeated all fellow members of the Big Four. In 2010 Federer finished in the top two for the eighth consecutive season.

2011: Tour Finals title record
Main article: 2011 Roger Federer tennis season
The year 2011 was a lean year for Federer, although great by most player's standards. He was defeated in straight sets in the semifinals of the 2011 Australian Open by eventual champion Novak Djokovic, marking the first time since July 2003 that he did not hold any of the four major titles. In the French Open semifinals, Federer ended Djokovic's undefeated streak of 43 consecutive wins with a four-set victory. Federer then lost in the final to Rafael Nadal. At Wimbledon Federer advanced to his 29th consecutive Grand Slam quarterfinal, losing to Jo-Wilfried Tsonga. It marked the first time in his career that he had lost a Grand Slam tournament match after winning the first two sets.

At the US Open Federer lost in the semifinals to Novak Djokovic in five sets. In a repeat of previous year's semifinal event, Federer again squandered two match points on his own serve before losing after winning first two sets for second consecutive time in the year. The loss meant that it was the first time since 2002 that Federer had not won any of the four grand slam titles.

In September 2011, in a South African poll, Federer was voted the second most trusted and respected person in the world next to Nelson Mandela.

Federer finished the season successfully in the indoor season, winning his last three tournaments of the year at the Swiss Indoors, Paris Masters, and ATP Finals, forming a 16 match winning streak. Federer finished the year ranked No. 3.
### Response: 2009 was arguably the most important of his career since he won his first and only French Open title, completing the career grand slam. He was also able to surpass Pete Sampras' record of fourteen men's grand slam titles.

Until then, Federer had won the three other grand slams - Wimbledon, Australian Open and US Open but the French Open was elusive as he had to repeatedly compete on the clay court of Rolland Garros against Rafael Nadal, who was a clay court expert and he lost to him on multiple occasions.

2004 was also an important year in Federer's career because he established dominance in the sport by winning three out of the four grand slams of the year and ending the year as the world number one for the first time in his long career.