Martina Hingis's 1998 decline continued yesterday. The world number one is unlikely to stay much longer at the pinnacle after missing a match point against her Swiss compatriot, Patty Schnyder, in the Compaq Grand Slam Cup semi-final before conceding with cramp at 5-5 in the final set.

Well before the end of a match lasting two hours 11 minutes, it was apparent that Hingis's mobility and stamina might not see her through. It was the second time in a fortnight that she has suffered from cramp and, worse still, she admitted she has a long-term fitness problem.

"I am not in the best of shape but I will learn from this," she said after losing 7-5, 5-7, 5-5 retired.

Hingis might have avoided the loss had she played a little more cannily.

She led 5-1 in the final set but failed to convert the match point at 5-2 on her serve when she hurried a backhand drive. Almost as vital was the good-length lob that struck one of the draped flags during a rally that might have taken her to 6-6 in the second set. When Hingis lost that set she kicked out at a ball in anger, and accidentally trod on another. She knew she was in difficulty.

For much of the match Hingis had become involved in heavy baseline exchanges with a 19-year-old whose ground-strokes are far more potent this year.