The US Open women's singles final between Serena Williams and Victoria Azarenka was postponed until Sunday after storm-battered New York was put on tornado watch.
The decision was taken just as the US Weather Service placed the area under tornado watch until 2100 local time (0100GMT), two hours after the scheduled start time of the women's final.
"The weather forecast for this evening is calling for storms with heavy rain and high winds," said a tournament spokesman.
"Due to the severe weather forecast, session 25 featuring the Women's Singles Final will be postponed until Sunday, September 9, 2012. We will confirm the start time for the Women's Final by 7:00 p.m. ET (2300GMT) this evening."
It will be the fourth time in five years that the women's final has been played on the Sunday rather than Saturday.
The men's singles final has been pushed back to the Monday for the last four years.
Play on Saturday had already been delayed following heavy rain and a tornado warning which had been issued following a twister briefly making landfall on the nearby Rockaway Peninsula.
The first men's semi-final between Andy Murray and Tomas Berdych got underway 90 minutes late on Arthur Ashe Stadium.
The second semi-final featuring defending champion Novak Djokovic and David Ferrer was still set to go-ahead as planned.
"We are continuing the day session as scheduled and will closely monitor the weather for the remainder of today's day session," added the spokesman.
Serena Williams will on Sunday be going for a fourth US Open title in six finals while Australian Open champion Azarenka, the world number one, is making her New York championship match debut.
"its sunshine,but very windy..and we r not going to play tonight - well I will go the gym then," Azarenka tweeted.
British third seed Murray, the 2008 runner-up, and Berdych, who knocked out five-time champion Roger Federer in the quarter-finals, battled high winds throughout their tie.
In the first set, Murray, with actor and fellow Scot Sean Connery watching from the stands, agreed to replay a point after Berdych insisted that he had been distracted by his opponent's white cap being blown onto the court as he chased down a drop shot.
Later, as the strong gusts continued, Berdych's bag was blown onto the court.
Despite the testing conditions, the deluge and continuing storms didn't dampen everyone's spirits at Flushing Meadows.
"Supposed to interview James Blake. He's caught in the traffic & I don't want to ruin my shoes," tweeted 1979 and 1981 champion Tracy Austin, now working as a TV analyst.
US tennis legend John McEnroe tweeted: "A tornado warning??? You cannot be serious!!!"