The US Open, formally the United States Open Tennis Championships, is a tennis tournament which is the modern incarnation of one of the oldest tennis championships in the world, with the U.S. National Championship, which for men's singles was first contested in 1881. Since 1987, the US Open has been chronologically the fourth and final tennis major comprising the Grand Slam tennis tournament each year. Rafael Nadal is the most recent men's single winner in 2010.
It is held annually in August and September over a two-week period (the weeks before and after Labor Day weekend). The main tournament consists of five different event championships: men's and women's singles, men's and women's doubles, and mixed doubles, with additional tournaments for senior, junior, and wheelchair players. Since 1978, the tournament has been played on acrylic hard courts at the USTA Billie Jean King National Tennis Center at Flushing Meadows-Corona Park in Queens, New York City.
The US Open is unique in that there are final-set tiebreaks; in the other three Grand Slam tournaments, the deciding set (fifth for men, third for women) continues until it is won by two games.