Some facts on US Open !

The US Open has developed from an exclusive entertainment event for high society to a championship for more than 600 male and female professional players who, as of 2008, compete for a total prize money of over US$19 million, with $1.5 million for each winner of the singles tournaments.

In the early years of the United States National Championship, only men competed, and only in singles competition.

The tournament was first held in August 1881 at the Newport Casino, Newport, Rhode Island and in that first year only clubs that were members of the United States National Lawn Tennis Association were permitted to enter.

From 1884 through 1911, the tournament used a challenge system whereby the defending champion automatically qualified for the next year's final.

In 1915, the tournament moved to the West Side Tennis Club at Forest Hills, New York. From 1921 through 1923, it was played at the Germantown Cricket Club in Philadelphia and returned to Forest Hills in 1924.

Six years after the men's nationals were first held, the first official US Women's National Singles Championship was held at the Philadelphia Cricket Club in 1887, followed by the US Women's National Doubles Championship in 1889.

The first US Mixed Doubles Championship was held alongside the women's singles and doubles. The first US National Men's Doubles Championship was held in 1900.

Tournaments were held in the east and the west of the country to determine the best two teams, which competed in a play-off to see who would play the defending champions in the challenge round.

The open era began in 1968 when all five events were merged into the US Open, held at the West Side Tennis Club in Forest Hills, New York. The 1968 combined tournament was open to professionals for the first time. That year, 96 men and 63 women entered the event, and prize money totaled $100,000.

In 1970, the US Open became the first of the Grand Slam tournaments to use a tiebreak at the end of a set.

The US Open was originally played on grass until Forest Hills switched to Har-Tru clay courts in 1975.

In 1978, the event moved from Forest Hills to its current home at Flushing Meadows, and the surface changed again, to the current DecoTurf. (Jimmy Connors is the only man to have won the US Open on more than one surface. He won it on all three surfaces. Female player Chris Evert won it on two surfaces.)

In 2006, the US Open became the first Grand Slam tournament to implement instant replay reviews of calls, using the Hawk-Eye computer system. Available only on the stadium courts (Ashe and Armstrong), each player was allowed two challenges per set plus one additional challenge during a tiebreak but was not penalized with the loss of a challenge if it was upheld. The USTA announced that starting in 2008, each player will be given three challenges per set with an extra challenge if the set goes to a tiebreak.