NEW YORK - SEPTEMBER 04: Roger Federer of Switzerland celebrates after defeating Gilles Muller of Luxembourg during the men's quarterfinals match on Day 11 of the 2008 U.S. Open at the USTA Billie Jean King National Tennis Center on September 4, 2008 in the Flushing neighborhood of the Queens borough of New York City.
NEW YORK - SEPTEMBER 04: Roger Federer of Switzerland reacts after defeating Gilles Muller of Luxembourg during the men's quarterfinals match on Day 11 of the 2008 U.S. Open at the USTA Billie Jean King National Tennis Center on September 4, 2008 in the Flushing neighborhood of the Queens borough of New York City.
NEW YORK - SEPTEMBER 04: Roger Federer of Switzerland returns to Gilles Muller of Luxembourg during the men's quarterfinals match on Day 11 of the 2008 U.S. Open at the USTA Billie Jean King National Tennis Center on September 4, 2008 in the Flushing neighborhood of the Queens borough of New York City.
NEW YORK - SEPTEMBER 04: Roger Federer of Switzerland serves to Gilles Muller of Luxembourg during the men's quarterfinals match on Day 11 of the 2008 U.S. Open at the USTA Billie Jean King National Tennis Center on September 4, 2008 in the Flushing neighborhood of the Queens borough of New York City.
NEW YORK - SEPTEMBER 04: Roger Federer of Switzerland follows through on his forehand to Gilles Muller of Luxembourg during the men's quarterfinals match on Day 11 of the 2008 U.S. Open at the USTA Billie Jean King National Tennis Center on September 4, 2008 in the Flushing neighborhood of the Queens borough of New York City.
NEW YORK - SEPTEMBER 04: Roger Federer of Switzerland reacts after winning the first set against Gilles Muller of Luxembourg during the men's quarterfinals match on Day 11 of the 2008 U.S. Open at the USTA Billie Jean King National Tennis Center on September 4, 2008 in the Flushing neighborhood of the Queens borough of New York City.
NEW YORK - SEPTEMBER 04: Roger Federer of Switzerland returns to Gilles Muller of Luxembourg during the men's quarterfinals match on Day 11 of the 2008 U.S. Open at the USTA Billie Jean King National Tennis Center on September 4, 2008 in the Flushing neighborhood of the Queens borough of New York City.
NEW YORK - SEPTEMBER 04: Roger Federer of Switzerland reacts while taking on Gilles Muller of Luxembourg during the men's quarterfinals match on Day 11 of the 2008 U.S. Open at the USTA Billie Jean King National Tennis Center on September 4, 2008 in the Flushing neighborhood of the Queens borough of New York City.
NEW YORK - SEPTEMBER 04: Roger Federer of Switzerland celebrates after defeating Gilles Muller of Luxembourg during the men's quarterfinals match on Day 11 of the 2008 U.S. Open at the USTA Billie Jean King National Tennis Center on September 4, 2008 in the Flushing neighborhood of the Queens borough of New York City.
NEW YORK - SEPTEMBER 04: Roger Federer of Switzerland celebrates after defeating Gilles Muller of Luxembourg during the men's quarterfinals match on Day 11 of the 2008 U.S. Open at the USTA Billie Jean King National Tennis Center on September 4, 2008 in the Flushing neighborhood of the Queens borough of New York City.
NEW YORK - SEPTEMBER 04: Roger Federer of Switzerland celebrates after defeating Gilles Muller of Luxembourg during the men's quarterfinals match on Day 11 of the 2008 U.S. Open at the USTA Billie Jean King National Tennis Center on September 4, 2008 in the Flushing neighborhood of the Queens borough of New York City.
NEW YORK - SEPTEMBER 04: Roger Federer of Switzerland celebrates after defeating Gilles Muller of Luxembourg during the men's quarterfinals match on Day 11 of the 2008 U.S. Open at the USTA Billie Jean King National Tennis Center on September 4, 2008 in the Flushing neighborhood of the Queens borough of New York City.
NEW YORK - SEPTEMBER 04: Roger Federer of Switzerland celebrates after defeating Gilles Muller of Luxembourg during the men's quarterfinals match on Day 11 of the 2008 U.S. Open at the USTA Billie Jean King National Tennis Center on September 4, 2008 in the Flushing neighborhood of the Queens borough of New York City.
NEW YORK - SEPTEMBER 04: Roger Federer of Switzerland returns to Gilles Muller of Luxembourg during the men's quarterfinals match on Day 11 of the 2008 U.S. Open at the USTA Billie Jean King National Tennis Center on September 4, 2008 in the Flushing neighborhood of the Queens borough of New York City.
NEW YORK - SEPTEMBER 04: Roger Federer of Switzerland serves to Gilles Muller of Luxembourg during the men's quarterfinals match on Day 11 of the 2008 U.S. Open at the USTA Billie Jean King National Tennis Center on September 4, 2008 in the Flushing neighborhood of the Queens borough of New York City.
NEW YORK - SEPTEMBER 04: Roger Federer of Switzerland serves to Gilles Muller of Luxembourg during the men's quarterfinals match on Day 11 of the 2008 U.S. Open at the USTA Billie Jean King National Tennis Center on September 4, 2008 in the Flushing neighborhood of the Queens borough of New York City.
NEW YORK - SEPTEMBER 04: Roger Federer of Switzerland returns to Gilles Muller of Luxembourg during the men's quarterfinals match on Day 11 of the 2008 U.S. Open at the USTA Billie Jean King National Tennis Center on September 4, 2008 in the Flushing neighborhood of the Queens borough of New York City.
NEW YORK - SEPTEMBER 04: Roger Federer of Switzerland returns to Gilles Muller of Luxembourg during the men's quarterfinals match on Day 11 of the 2008 U.S. Open at the USTA Billie Jean King National Tennis Center on September 4, 2008 in the Flushing neighborhood of the Queens borough of New York City.
NEW YORK - SEPTEMBER 04: Roger Federer of Switzerland returns to Gilles Muller of Luxembourg during the men's quarterfinals match on Day 11 of the 2008 U.S. Open at the USTA Billie Jean King National Tennis Center on September 4, 2008 in the Flushing neighborhood of the Queens borough of New York City.
NEW YORK - SEPTEMBER 04: Roger Federer of Switzerland reacts while taking on Gilles Muller of Luxembourg during the men's quarterfinals match on Day 11 of the 2008 U.S. Open at the USTA Billie Jean King National Tennis Center on September 4, 2008 in the Flushing neighborhood of the Queens borough of New York City.