Serena Williams says she's pulled out of next week's Fed Cup final because she' physically and mentally exhausted.
The 28-year-old hasn't played for the United States since 2007 and withdrew just days after being named in the squad to face Italy.
She says she really wanted to play but didn't think she'd do well physically after beating her sister
Venus to win the WTA Championships on Sunday, finishing the Doha tournament with her left thigh heavily strapped.
The loss of both sister is a big blow to the USA's chances of winning the winning the Cup for the first time in nine years
Serena Williams will end the year as world number one after winning five matches in six days.