KITZBUEHEL, Austria (AP) Top-seeded Dominic Thiem reached his third semifinal in as many weeks after his opponent Albert Montanes of Spain pulled out injured at the Generali Open on Thursday.

Thiem led 7-6 (3), 3-2 when Montanes, who received medical treatment on his left ankle in the opening set, quit the quarterfinal.

Coming off back-to-back tournament wins in Umag and Gstaad, the 21st-ranked Austrian is unbeaten for 10 straight matches. He next takes on Philipp Kohlschreiber of Germany, while French qualifier Paul-Henri Mathieu and Nicolas Almagro of Spain will contest the other semifinal.

''I feel sorry for Albert and for the fans, but I am happy,'' Thiem said.

He missed a set point at 5-4 in the opening set before dominating the tiebreaker. He was a break up in the second set when Montanes withdrew.

Kohlschreiber defeated the third-seeded Fabio Fognini of Italy 7-6 (0), 6-4 to advance to his second semifinal of the season after reaching the final in Munich in May.

The 39th-ranked Kohlschreiber, 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.

Mathieu advanced to his first semifinal of the year by beating Federico Delbonis of Argentina 6-3, 0-6, 6-3, while Almagro defeated Dusan Lajovic of Serbia 6-3, 6-4.