Schnyder dropped the opening set 7-5 but took the second by the same margin before fighting back from 5-1 down in the third, saving a match point along the way.

Hingis, who is in danger of losing her number one spot to American Lindsay Davenport next week in Fildertadt, Germany, was leading 5-4 in the third when she received treatment on her right thigh for several minutes.

She resumed playing but then dropped her serve and quit saying she was suffering from cramp.

World number nine Schnyder, who had never met Hingis before, will face either American Venus Williams or France's Nathalie Tauziat in Sunday's final.

Women are appearing for the first time in the $<\!q>6.7 million event for the best performers in the year's four Grand Slams.

Rios fixes Felix

World number three Marcelo Rios won aclose battle of baseliners, beating Spaniard Felix Mantilla 7-6, 7-5 to reach the semifinals last night.

Rios, the highest ranked player in the men's draw of the tournament for the best performers in the year's four Grand Slams, now faces an appetising clash with hard-hitting Australian Mark Philippoussis for a place in Sunday's final.

Chilean Rios, a finalist at the Australian Open last January, needed a tie break, which he took 7-2, to claim the first set.

French Open semifinalist Mantilla kept fighting in the second set until Rios used a rare backhand volley on match point to seal victory and make sure of at least $375,000 in prize money.

Earlier, Philippoussis relied on his heavy artillery to down Swede Jonas Bjorkman, firing 13 aces on his way to a 4-6, 7-6, 6-1 quarter-final victory.

Bjorkman countered the US Open finalist's missiles with brilliant returns to win the first set but Philippoussis moved up a gear in the second, forcing a tie break which he took 7-1 with an ace on setpoint.

From then on, the hard-hitting Australian was in a class of his own, firing winners almost at will to open up a 4-0 lead in the decisive set before seeing Bjorkman hit a forehand into the net on match point.