MOSCOW (AP) -- Samantha Stosur and doubles partner Svetlana Kuznetsova will meet in the Kremlin Cup semifinals after both players won in straight sets Friday.
Stosur extended her unbeaten run to eight matches by defeating former No. 1 player Ana Ivanovic 7-5, 6-4. Kuznetsova eliminated second-seeded Roberta Vinci 6-2, 6-3.
Defending men's champion Andreas Seppi of Italy made it to his fifth semifinal of the season after Edouard Roger-Vasselin retired because of a strained neck while trailing 5-2.
Seppi will next play Mikhail Kukushkin, who beat Andrey Golubev 6-4, 7-6 (4). Croatia's Ivo Karlovic advanced to his second semifinal of the season by winning eight consecutive games and serving 11 aces to rout Russian teenager Karen Khachanov 6-4, 6-0.
Stosur vs. Ivanovic was a rematch of last year's three-set semifinal between former Grand Slam champions. Ivanovic took a 3-0 lead but Stosur broke back twice to win the first set. An early break in the second was enough for the Australian to defeat Ivanovic for the second straight year.
''Probably having a match won here last year, I certainly had a few things in my head that I wanted to try to do today against her,'' Stosur said. ''And right from the start it was kind of working and from that my confidence kind of built, and I was able to keep going and play well till the end.''
Last Sunday, Stosur won the fifth title of her career in Osaka, Japan, while Ivanovic lost in the final in Linz, Austria.
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.
''Today I played really well in the first set with some slight mistakes in the second, which I managed to overcome,'' Kuznetsova said. ''I hope I'll be able to boost my performance in the next matches as well.''
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 hurt his neck during the warmup and needed treatment after the first game.
''From his first service game and down in the match he couldn't serve normally,'' Seppi said. ''I would never like to win like this, but sometimes it happens.''