Roger Federer is a Swiss professional tennis player. He was ranked world No. 1 by the Association of Tennis Professionals for 310 weeks, including a record 237 consecutive weeks, and has finished as the year-end No. 1 five times. He has won 103 ATP singles titles, the second most of all time, including 20 Grand Slam singles titles, a record eight men's singles Wimbledon titles, an Open Era record-tying five men's singles US Open titles, and a record six year-end championships. Federer has played during an era where he dominated men's tennis along with Rafael Nadal and Novak Djokovic as the Big Three, collectively considered by some to be the three most successful male tennis players of all time. A Wimbledon junior champion in 1998 and a former ball boy, Federer won his first major singles title at Wimbledon in 2003 at age 21. Between 2003 and 2009, he made 21 out of 28 major singles finals.