Madrid - French Open champion Ana Ivanovic Friday withdrew from the Madrid Masters starting on Saturday with inflammation of the right knee.

Ivanovic has been ordered to rest for a week by doctors with a fortnight to go before her title defence at the clay-court Grand Slam at Roland Garros.

"I'm so disappointed to be missing Madrid," said Ivanovic, who owns a holiday home in Mallorca and has been learning Spanish. "When I saw the 2009 calendar this was one of the events that I was most looking forward to, because I love Spain.

"I visited the (new tournament venue) Caja Magica two years ago and it looked like a beautiful stadium. I'm very sad that I won't be there.

"At the moment there is no danger of me missing Paris: my focus is now on Roland Garros."

Ivanovic, who went out in the Rome third round to Agnieszka Radwanska, said she has had the knee problem since last month.

"It's been bothering me since the Fed Cup a couple of weeks ago. It's become more painful with each match so I decided to go and see a specialist in Munich," said the Serb.

"Unfortunately he and his staff told me that I need to take a break from playing matches, although I must work hard on my recovery during the next week. It's very frustrating because I feel that my overall fitness is at its peak, and I have been practising very well.

Women's play in Madrid starts on Sunday with men at the joint event going into action on Sunday.

Missing the required WTA tournament will cost Ivanovic a place in the year-end bonus pool with loss a of up to a quarter of a million dollars in potential payouts.

She must also visit Madrid over the next year to perform promotional activities to avoid a fine and possible suspension. (dpa)