Roger Federer (born 8 August 1981) is a Swiss professional tennis player who held the ATP number one position for a record 237 consecutive weeks. As of 9 January 2011, he is ranked World No. 2 by the Association of Tennis Professionals (ATP). Federer has won a male record 16 Grand Slam singles titles, holding at least one Grand Slam title every single week from Wimbledon 2003 until the Australian Open in 2011. He is one of seven male players to capture the career Grand Slam and one of three (with Andre Agassi and Rafael Nadal) to do so on three different surfaces (clay, grass and hard courts). Many sports analysts, tennis critics, former and current players consider Federer to be the greatest tennis player of all time.