DOHA (AFP) - Venus Williams breathed a sigh of relief when she discovered she had been overlooked for America's Fed Cup final team, admitting her usual power-packed batteries are running desperately low.

The 29-year-old insists that talk of retirement is premature, but after suffering a second defeat in two matches at the WTA Championships here, the former world number one will be glad of a break.

"I can't play after that. I just can't. I can't do it," said Williams, the defending champion here but now virtually eliminated from the eight-woman tournament.

Williams's second defeat came at the hands of sister Serena in a three-set, three-hour marathon and a tie in which she had held a match point.

Serena will be part of the US team to tackle Italy in the Fed Cup final next month, and Venus insists her compatriots can shine without her.

"The team got to the final without me, so they can definitely win without me," she said.

"I've given a lot of time to Fed Cup over the years. I'm just unable to play more tennis after this Championship."

Earlier in 2009, Williams clinched the 40th and 41st titles of her career with trophies in Dubai and Acapulco, but the eight months since have witnessed a title drought.

She even lost her Wimbledon crown to Serena.

As far as 2010 is concerned, she appreciates there are improvements to be made; she is just not sure where or how.

"There's a lot of things that can be done. But I'm not sure that I have the answer quite yet," she said.