Former world number one Martina Hingis was beaten in three sets by Flavia Pennetta on Friday as her comeback winning streak ended in the semi-finals of the Australian women's hardcourt event.
In her fourth singles match since returning to professional tennis after a three-year lay-off, Hingis took the first set easily before succumbing to the Italian world number 23 in a tie-break second.
The five-time Grand Slam winner faded in the final set to lose 1-6 7-6 (7/2) 6-2.
Hingis and France's Tatiana Golovin also pulled out of the doubles semi-final against Zimbabwe's Cara Black and Australian Rennae Stubbs. No reason has been given for their withdrawal.
Hingis, 25, retired in 2002 with foot, heel and ankle injuries, but has signalled her intention to make a serious comeback here.
She is set to play in the Sydney International later this month before taking a wild card entry to compete in the Australian Open beginning January 16.
Pennetta will meet 18-year-old Lucie Safarova of the Czech Republic, who recorded a solid 6-4 6-2 win over world number 20 Dinara Safina, in Saturday's final.
{{/usCountry}}Pennetta will meet 18-year-old Lucie Safarova of the Czech Republic, who recorded a solid 6-4 6-2 win over world number 20 Dinara Safina, in Saturday's final.
{{/usCountry}}Safarova ousted Japan's Ai Sugiyama in the first round and defending champion world number seven Patty Schnyder in Thursday's quarter-final.