Slovakia's Daniela Hantuchova upset third-seeded Svetlana Kuznetsova of Russia 6-4 6-2 on Sunday to reach the final of the Zurich Open.
Her opponent in Monday's showdown will be second-seeded Russian Maria Sharapova, who reached her sixth final of the year when she defeated unseeded Katarina Srebotnik of Slovenia 7-6 6-2.
Kuznetsova was a pale reflection of the woman who played brilliantly to dispose of Martina Hingis in Friday's quarter-finals, finding difficulty with her serve and failing to maintain the rallies against a confident and consistent opponent.
Hantuchova broke to lead 2-1 when Kuznetsova dumped a smash into the net and although Kuznetsova levelled at 4-4 she then hit two successive double-faults to concede her serve again and leave Hantuchova serving for the set.
Hantuchova again broke for 2-1 in the second set when Kuznetsova netted a forehand, and the Russian called for medical attention to her right foot after Hantuchova held serve for 4-2.
When play resumed after several minutes, Hantuchova broke for 5-2 and went on to close out the match on her third match point.
The Slovak revealed that she might not have been able to play this week after she was struck by a ball in a doubles match.
"I was hit really hard in the doubles and it was really hurting me, and I wasn't sure if I was going to be able to play," Hantuchova told reporters.
"It happened in our first doubles match. Mary Pierce just went for one of her big shots with the forehand and it went straight in the rib. It was hard to get my breath.
"In the first two days it was not really fun because I couldn't really get up on my serve and stretch. When things like that happen you just have to be strong mentally and not let it affect you."
Sharapova, who will try to add to her US Open, Indian Wells and San Diego triumphs, had not performed at her best throughout the week.
Once again she played an erratic match against an opponent who served well and played competently from the baseline but lacked any weapon to cause the Russian real problems.
Sharapova dropped only two points on serve until, at 4-4, Srebotnik donated four errors to lose serve to love. Instead of building on the gift, however, Sharapova responded in kind and allowed Srebotnik to level at 5-5.
Srebotnik held a set point at 6-5 which Sharapova saved with her fifth ace and the Russian went on to take the tiebreak 7-3.
A crosscourt winner gave Sharapova a break to lead 2-0 in the second set but Srebotnik broke back in the fifth game and Sharapova received a warning for coaching.
Raising her aggression level, Sharapova broke again for 4-2 by forcing a backhand error and again for the match when she forced Srebotnik to net a backhand volley at close range.
"It was definitely a step up from my previous matches," said Sharapova. "I felt I was in control, I was moving better and definitely played the big points good."