"Whenever there is a serious injury it can be really difficult," said Kournikova, who had to sit out much of last year with a stress fracture to her foot and currently has a groin strain.

"Right now I have a groin problem but I know it's going to go away in a week or so many days, so it's not like a bone or a joint or something major. That kind of thing is totally different."

Kournikova confirmed she had spoken to Hingis but refused to reveal the details of their conversation. "I don't think I want to talk about that," she said.

The Russian, however, did say that she was concerned about her friend. "I guess in Martina's case we don't know what exactly the problem is yet and how serious," she said. "So we keep our fingers crossed to see the results."