The men's singles' rules have undergone several changes since the first edition. From
1884 to
1911, the event started with a
knockout phase, the All-Comers singles, whose winner faced the defending champion in a
challenge round. The All-Comers winner was awarded the title six times (
1888,
1893,
1898,
1901,
1904,
1907) in the absence of the previous year's champion. The challenge round system was abolished with the
1912 edition. From 1908 to 1914, when the championships were held at Newport, men's singles draws had exceeded 128 players, but when the event moved to Forest Hills in 1915 entries would be "submitted by clubs, thereby making the clubs weed out mediocre players. Furthermore, the entry fee would be set high enough to prevent cheapskates from entering just to get a seat at the tournament at a lower price and then defaulting". From 1881, all matches but the All-Comers final and the challenge round were played as the
best-of-three sets, before the event switched to
best-of-five for all rounds in
1886. Best-two-out-of-three-sets matches were reintroduced for early rounds in
1917, from
1943 to
1945, and from
1975 to
1978. In addition, the US Open was the first slam to have a fifth set tie-break. The court surface changed twice, from
grass (1881–1974), to
Har-Tru clay (1975–1977), to
DecoTurf hard courts, since 1978. The only man to win on all three surfaces, which are grass, Har-Tru clay, and DecoTurf hard was
Jimmy Connors. The champion receives a full-size replica of the event's trophy engraved with his name. In 2010, the winner received prize money of US$1,700,000. A bonus pool of $1,000,000 is also to US Open champions who have clinched the first place of the
US Open Series. In the U.S. National Championships,
Richard Sears (1881–1887),
William Larned (1901–1902, 1907–1911) and
Bill Tilden (1920–1925, 1929) hold the record for most titles in the men's singles, with seven victories each. Four of Sears' wins and all of Larned's, came in a time when the tournament used a challenge round format, and they won respectively only three times and twice after going through a complete draw. Sears also holds the all-time record for most consecutive titles, with seven from (1881 to 1887); the first win came when the event was closed to foreign participants. Without the challenge round, the record stands at six, and is held by Tilden (1920–1925). During the US Open, since the inclusion of the professional tennis players, Jimmy Connors (1974, 1976, 1978, 1982–1983),
Pete Sampras (1990, 1993, 1995–1996, 2002), and
Roger Federer (2004–2008) have won the most championships, with five titles. Federer has had the most consecutive wins, with five (2004–2008). ==Champions==