Serena Williams has pulled out of next week’s Fed Cup final against Italy.

The new world number one made the decision after winning the end of season Sony Ericsson Championships against her sister Venus, feeling that she wouldn’t be physically capable of performing again after just a week’s rest.

Serena was keen to stress all last week in Doha, just how much she wanted to win the tournament. She said several times in press conferences that she was going to give everything to have a chance of winning. Mainly she didn’t need to, she was only once taken to three sets, by Venus in the round-robin stages but it was still a mentally draining week.

In her press conference after winning the final, Serena apologised to her team-mates on the USA team saying, "It's very difficult to play such a mental week and then come back and play again. Right now I'm just struggling in every aspect of my body. Pulling out of the Fed Cup final was a very difficult decision that I actually couldn't make. I had to get input from my mom and my dad. People that are close to me had to just basically tell me what I needed to do as opposed to me making the decision."

Serena’s absence now means that Italy will be favourites to win. With Flavia Pennetta and Francesca Schiavone they have the more experienced team. The USA will be relying a lot of new American starlet Melanie Oudin.