Janko Tipsarevic reached the Erste Bank Open semifinals after Aljaz Bedene retired with a left thigh injury during their match on Friday.
The ninth-ranked Serb, who was leading 6-2, 4-2, will play either third-seeded Tommy Haas or Grega Zemlja for a place in Sunday's final.
Bedene was broken at 2-2. Tipsarevic dominated the match from then on as Bedene became hampered by the injury.
Also, Gilles Muller of Luxembourg advanced after defeating Paolo Lorenzi 6-3, 6-4. Muller had 10 aces and used one break in each set to reach his second semifinal of the year.
He will play either top-seeded Juan Martin del Potro or Marinko Matosevic.