Second-seeded Sloane Stephens of the United States was upset 6-7 (3), 6-4, 7-5 Friday by Stefanie Voegele in the quarterfinals of the Generali Ladies.
The 12th-ranked Stephens lost the last five games of the final set. Stephens also lost a 5-2 lead in the opening set before converting her ninth set point in the tiebreaker. Voegele used one break to take the second set and won the third after trailing 5-2.
The 58th-ranked Voegele will play two-time former champion Ana Ivanovic or Dominika Cibulkova in an attempt to reach her first career final.
Also, fourth-seeded Carla Suarez Navarro of Spain beat Kirsten Flipkens of Belgium 6-1, 6-3. Suarez Navarro won the first eight points of the match and held serve throughout.
She'll play either top-seeded Angelique Kerber or Patricia Mayr-Achleitner.