(Reuters) - The remnants of Hurricane Isaac dumped rain on the U.S. Open on Tuesday, forcing the suspension of play and threatening to cause extended delays to the last grand slam of the year.

Play was suspended after 10 minutes of action on Tuesday morning when heavy rain began falling on Flushing Meadows, forcing players and spectators to run for cover.

The prospect of further disruptions was high with prolonged thunderstorms forecast for the next two days, raising the possibility of flash floods on the U.S. East Coast.

One singles match was underway when the rain arrived. World number one Victoria Azarenka of Belarus was playing defending champion Samantha Stosur of Australia in the quarter-finals.

Azarenka, who won the Australian Open this year, grabbed the early initiative, breaking Stosur's serve twice to snatch a 3-0 lead in the first set before the darkened clouds erupted above.

Stosur was one of five former U.S. Open champions scheduled to play on Tuesday.

Serbia's Novak Djokovic, the defending men's champion, was due to face Switzerland's Stanislas Wawrinka in the fourth round while American Andy Roddick, the 2003 champion who is retiring after the tournament, is set to meet towering Argentine Juan Martin del Potro, the 2009 winner, for a place in the quarters.

In the women's quarters, Russia's Maria Sharapova, champion in 2006, was due to play Marion Bartoli of France.

At least 30 people were killed by Hurricane Isaac during its deadly trek across the Caribbean, Louisiana and Mississippi that left around half a million homes without power before weakening and heading inland through the U.S. Midwest and East Coast.