Top-seeded Stan Wawrinka cruised past seventh-seeded Viktor Troicki on Friday to reach the semifinals of the St. Petersburg Open in Russia.
Wawrinka, the U.S. Open champion, needed just 64 minutes to post a 7-5, 6-2 quarterfinal victory over the Serbian.
Wawrinka, of Switzerland, will face fourth-seeded Roberto Bautista Agut of Spain in the semifinals. Agut defeated eighth-seeded Joao Sousa of Portugal 4-6, 6-1, 6-2 in the quarterfinals.
Third-seeded Tomas Berdych of the Czech Republic advanced to the semifinals with a 6-4, 6-3 victory over Italy's Paolo Lorenzi.
Thiem reaches Moselle Open semifinals
The Austrian recorded 16 aces while notching the straight-set victory.
"I'm very happy about the match because the return is one of my biggest weaknesses and it's always tough against a good server like Gilles," Thiem told reporters. "The first set I returned really well. ... I broke him and I also had chances to break a second time."
Thiem will face fourth-seeded Gilles Simon on France in the semifinals. Simon recorded a 7-6 (2), 6-0 victory over Malek Jaziri of Tunisia.
Second-seeded David Goffin of Belguim and third-seeded Lucas Pouille will square off in the other semifinal.
Goffin registered a 6-3, 6-7 (6), 6-4 win over eighth-seeded Nicolas Mahut of France, while Pouille advanced with a 7-6 (2), 4-6, 6-3 victory over fellow Frenchman Julien Benneteau.