Melbourne  - Jelena Dokic has been ordered to rest for another fortnight after doctors diagnosed the Australian as suffering with glandular fever over the past several months.

Tennis Australia revealed the surprise development Friday after the Australian Open quarter-finalist left the court with back pain in the second round of the French Open and lost her opening match at Wimbledon while complaining of feeling ill.

The Australian had blood tests after her Wimbledon loss and the results came back earlier this week. Doctors have told her to do nothing but rest for at least a fortnight.

"I'm disappointed to have to pull out of a couple of events but I am also relieved to finally know what was wrong," said Dokic. "It's been so frustrating since the French.

"My natural work ethic is to get on court and train hard with intensity. I just haven't been able to do that, and until now, I didn't know why."

The number 75 said the development "only makes me more determined to get everything right and work even harder as soon as I can get back on court, which will hopefully be in time for a good solid hard court lead up to the US Open."(dpa)