MOSCOW: Samantha Stosur will face doubles partner Svetlana Kuznetsova in the semifinals of the Kremlin Cup after both players won in straight sets Friday.

Stosur extended her unbeaten run to eight matches by defeating Ana Ivanovic 7-5, 6-4, while Kuznetsova beat second-seeded Roberta Vinci 6-2, 6-3.

Also, defending men’s champion Andreas Seppi of Italy made it into his fifth semifinal of the season after Edouard Roger-Vasselin retired with a neck strain while trailing 5-2.

In a rematch of last year’s three-set semifinal match between former Grand Slam champions, Ivanovic took a 3-0 lead but Stosur broke back twice to win the opener. An early break in the second set was enough for the Australian to defeat the former top-ranked Ivanovic for the second straight year.

Last Sunday, Stosur won the fifth title of her career in Osaka, Japan, while Ivanovic lost in the Linz final.

Kuznetsova, a two-time Grand Slam champion, broke twice in the first set. But Vinci offered more resistance in the second, trading breaks twice before the Russian took a 4-2 lead.

The Russian will be playing in her first semifinal this season and her first at a home event since she lost to Serena Williams in 2007.

In the men’s tournament, Roger-Vasselin strained his neck during the warm-up and had it treated after the first game.

Seppi will next play Mikhail Kukushkin, who beat Andrey Golubev 6-4, 7-6 (4).

Croatian veteran Ivo Karlovic advanced to his second semifinal of the season by winning eight consecutive games and landing 11 aces to rout Russian teenager Karen Khachanov 6-4, 6-0.

Haas in last four at Vienna

In Vienna, Tommy Haas of Germany reached his seventh semifinal of the season by defeating fifth-seeded Radek Stepanek of the Czech Republic 7-6 (10), 6-3 at the Erste Bank Open on Friday.

The victory kept the 12th-ranked German in the running to qualify for next month’s ATP World Tour Finals in London.

Haas will face another Czech, eighth-seeded Lukas Rosol, for a place in Sunday’s final. Robin Haase of the Netherlands will take on either top-seeded Jo-Wilfried Tsonga or Dominic Thiem of Austria in the other semifinal.

Haas failed to serve out the opening set at 6-5 but won the tiebreaker after saving four set points for Stepanek. He converted his only break point in the second set.

Haase, who won both his career titles in Austria, rallied to defeat third-seeded Fabio Fognini of Italy 6-7 (4), 6-1, 6-1 to advance to his fourth semifinal of the season.

Haase didn’t face a break point in the entire match. Fognini had 32 baseline errors and ended the match with his second double-fault.

Earlier, Rosol beat Ruben Bemelmans of Belgium 6-3, 1-6, 6-3. Rosol broke the 176th-ranked qualifier once each in the first and final sets to reach his second career semifinal, and first since winning his maiden title in Bucharest in April.