Philipp Kohlschreiber of Germany defeated the third-seeded Fabio Fognini of Italy 7-6 (0), 6-4 to reach his second semifinal of the season at the Generali Open on Thursday.
The 39th-ranked Kohlschreiber, who is seeded sixth, saved two set points in the opening set before winning 16 of the first 20 points for a 4-0 lead in the second set.
Kohlschreiber, who reached the final in Munich in May, will play top-seeded Dominic Thiem or Albert Montanes in Friday's semifinals.
French qualifier Paul-Henri Mathieu advanced to his first semifinal of the year by beating Federico Delbonis of Argentina 6-3, 0-6, 6-3.
Mathieu will next take on Nicolas Almagro of Spain, who defeated Dusan Lajovic of Serbia 6-3, 6-4.