UNITED STATES - MARCH 11: Roger Federer of Switzerland returns the ball to Pete Sampras of the U.S. during a best-of-three-set exhibition match at Madison Square Garden in New York, U.S., on Monday, March 10, 2008. Federer, the world's No. 1-ranked player, defeated Sampras, who won a record 14 Grand Slam singles titles before retiring from the men's tennis tour, 6-3, 6-7 (4-7), 7-6 (8-6) on a hard-court surface at the indoor Manhattan arena. (Photo by Robert Caplin/Bloomberg via Getty Images)