(Reuters) - Factbox of 25 memorable moments, milestones of the 50-year-old U.S. Open tennis tournament played annually in New York:
1968 - Previously the U.S. national championships, the U.S. Open is played for the first time at the West Side Tennis Club with $100,000 in prize money.
1968 - Arthur Ashe, a lieutenant in the U.S. Army, takes leave to play in the tournament, becoming the first African-American to win a men’s single at a Grand Slam event when he outlasts Tom Okker of the Netherlands 14-12 5-7 6-3 3-6 6-3.
1969 - Rod Laver makes a big switch, to spikes because of the wet grass surface, to complete his second Grand Slam with a four-set victory over Tony Roche.
1970 - Margaret Smith Court becomes the second woman to win the Grand Slam with a 6-2 2-6 6-1 triumph over Rosie Casals. She wins all three U.S. Open titles that year, singles, doubles with Judy Dalton and mixed doubles with Marty Riessen.
There’s also a new addition at the tournament, the tiebreak which is used for the first time at a Grand Slam championship.
1971 - Chris Evert, only 16 and missing school, did her schooling on the court in her first U.S. Open, “Miss Poker Face” as pundits called her, advancing to the semi-finals in a tournament she would win six times.
1974 - The tournament is played on grass courts for the last time, and what a final as Billie Jean King defeats Evonne Goolagong 3-6 6-3 7-5 in what journalist/historian Steve Flink calls one of the four greatest U.S. Open matches.
1975 - The lights come on at Forest Hills enabling the U.S. Open for the first time to feature night matches.
1977 - The news isn’t that Renee Richards loses to Virginia Wade in the first round, but that a transgender player competes in the U.S. Open. Born Richard Raskind, he had played in five U.S. national championships before a sex-change operation in 1975. It took a New York court ruling two years later, and just two weeks before the tournament, for Richards to make history.
1978 - It’s moving time for the U.S. Open, which leaves the West Side Tennis Club for the National Tennis Center in Flushing Meadows and switches from clay to hard court surfaces
1979 - Has there ever been a match like the 1979 second round encounter between John McEnroe and Ilie Nastase? Upset at a third set call, Nastase pretends to go to sleep on court with his racket as a pillow and refuses to play.
Eventually the match is defaulted and awarded to McEnroe only for tournament director Bill Talbert, with beer cans and paper cups flying onto the court, rescinds the default, changes umpires and watches as McEnroe wins in four sets.
1979 - She was only 16, but what a player. Tracy Austin, in pigtails, beats Martina Navratilova and Chris Evert in successive matches to become the U.S. Open’s youngest winner.
1981 - One of the sport’s best rivalries ends with Wimbledon winner Bjorn Borg walking off the court following a four-set loss to John McEnroe. The Swede retires shortly thereafter.
1988 - Steffi Graf’s spectacular season is complete as she wins her fourth Grand Slam tournament of the calendar year, the last woman to do so.
1991 - Somehow Jimmy Connors, 17 years after his first U.S. Open title, makes it to the semi-finals after beginning the tournament ranked number 174 in the world. Along with the memorable wins are some choice words for a chair umpire after a ruling he dislikes in a fourth-round match. “I’m out here playing my butt off at 39-years-old and you’re doing that?” crowd favourite Connors is quoted as saying.
1995 - Steffi Graf and Monica Seles had met 10 times previously but this one was special, the first meeting between the two since a Graf fan stabbed Seles during a 1993 match in Germany. Graf prevails with the players hugging afterward.
1997 - Arthur Ashe Stadium, with 22,547 seats, opens, named in honour of the first man to win a U.S. Open title.
1999 - Serena Williams tops Martina Hingis to win the first of her six U.S. Open titles.
2001 - Venus versus Serena in the first Grand Slam singles final between sisters in more than a century. Venus wins in the first Grand Slam final between African-American players and in the first Open to offer equal pay for women and men.
2002 - Pete Sampras closes his career in storybook fashion as he defeats Andre Agassi in four sets for his fifth U.S. Open title
2006 - Andre Agassi’s career did not end with a win at the 2006 Open, but the emotions could not have been higher nor the applause longer after his third-round loss to Benjamin Becker. For four minutes fans stood and cheered before a tearful Agassi walks to centre court and blows kisses to the crowd.
2006 - On opening night, the U.S. Open facility is renamed the USTA Billie Jean King National Tennis Center. Instant replay also comes to the Open.
2008 - Roger Federer makes it five consecutive U.S. Open titles with a three-set triumph over Andy Murray. A year later the streak would end when Argentine Juan Martin del Potro, who had never beaten the world number one, pulls off a five-set surprise.
2009 - Serena Williams’ profane tirade after a line judge’s call results in Kim Clijsters being awarded a penalty point in their semi-finals. Since it came on match point, the match was over. Williams also was fined $82,500.
2009 - Kim Clijsters steals the hearts of U.S. Open fans when she becomes the first unseeded player to win an Open title, then poses on court with 18-month-old daughter Jada. It had been 29 years since a mother had won a Grand Slam title, Evonne Goolagong being the previous at Wimbledon in 1980.
2016 - Following years of rain delays and postponements, there’s a roof over Arthur Ashe Stadium court and on a rainy August night the $150 million high-tech retractable roof closes for the first time, allowing Rafael Nadal and Andreas Seppi to play on.
Reporting by Gene Cherry in Raleigh, North Carolina; Editing by Christian Radnedge