Injury-hit Steffi Graf has been forced to shelve her latest comeback after a recurrence of knee trouble. The 28-year-old former world number one had planned to return in next week's Pan Pacific Open in Tokyo after eight months on the sidelines.

But Graf, now ranked 30 in the world, was forced to concede last night that her comeback "would have to be delayed again" after her left knee, which was operated on last summer, flared up again.

"Up until two days ago my preparations were going fine. For a month now I've made good progress physically," Graf said. "But unfortunately on Wednesday, the night before I was due to fly out, I felt pain in my left knee again."