* Expected rainstorm causes delay
* Serena to face Azarenka for title
* Weather also slows men's play (Adds details)
NEW YORK, Sept 8 The U.S. Open women's final between American Serena Williams and Victoria Azarenka of Belarus has been postponed from Saturday night until Sunday due to an expected rainstorm and heavy winds, organisers announced.
The women's final had been scheduled to start at 7:00 p.m. (2300 GMT) Saturday at Flushing Meadows.
The start time for the women's final was not yet decided. The men's final is scheduled to be played on Sunday beginning 4:30 p.m. (2030 GMT).
Weather could further complicate scheduling at the roof-less Arthur Ashe Stadium.
Rain delayed the start of Saturday's men's semi-final between Olympic champion Andy Murray of Britain and Tomas Berdych of the Czech Republic for 90 minutes before they were able to take the court.
They were to be followed onto Arthur Ashe Stadium court by the second semi-final pitting defending champion Novak Djokovic of Serbia against Spain's David Ferrer, although more threatening weather was in the forecast.
Further delays could extend the championships to a Monday finish, which would mark the fifth year in a row that the year's final grand slam could not be completed by Sunday as scheduled. (Reporting by Larry Fine, Editing by Gene Cherry)