Sunday final for women

Court staff sweep away surface water at Flushing Meadows

The US Open women's singles final between Serena Williams and Victoria Azarenka has been postponed from Saturday until Sunday because of forecast heavy rains and storms, organisers announced.

"The weather forecast for this evening is calling for storms with heavy rain and high winds," said a US Open 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 pm ET (12pm BST) this evening."

Play on Saturday had already been delayed by 90 minutes following heavy rain and a tornado warning which had been issued for the New York area.

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 scheduled.

"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.

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 moved back to the Monday for the last four years.