NEW YORK, Sept 13 The US Tennis Association defended their decision to carry on staging the US Open without the benefit of a covered court even as rain on Sunday postponed the men's final for the third year in a row.

The rain forced world No 1 Rafa Nadal, seeking to become the seventh man to complete a career Grand Slam, and Serbian third seed Novak Djokovic to wait until Monday to contest the last Grand Slam final of the year.

Both the Australian Open and Wimbledon championships have retractable roofs to deal with dodgy weather and French Open officials have discussed the possibility.

“It's technically complex and financially challenging,” USTA spokesman Chris Widmaier said. “At a cost of more than $150 million, do you spend that on a roof or continue to fund grassroots tennis programs in this country?”

Widmaier said $100 million had been spent on improvements at the Flushing Meadows complex in the last five years, with the biggest expense being a new indoor training centre.

He also said money from the US Open was funneled into player development, grants and scholarships and to improving tennis facilities around the country, which included providing help to resurface 1,100 courts across the United States.

Widmaier said USTA president Lucy Garvin is heading a committee that will be make recommendations to the tennis association on future improvements to the National Tennis Center complex and some options being looked at included covering smaller courts at less expense.

Four-time US Open winner John McEnroe, now a TV commentator at the championships, said last year he had lobbied USTA officials from the start to put a roof over Arthur Ashe Stadium when it was built to replace Louis Armstrong Stadium in 1997 as the tournament's main stage.—Reuters