* Stosur, Ivanovic also advance to last four
* Men's semi-finals to feature first Tunisian (Updates with later matches, adds quotes, detail)
By Gennady Fyodorov
MOSCOW, Oct 19 Former world number one Caroline Wozniacki showed glimpses of her past form to beat last year's champion Dominika Cibulkova 6-2 6-7 6-1 in the Kremlin Cup quarter-finals on Friday.
The third seed from Denmark, looking for her second WTA title in a month after winning the Korea Open, will now take on unseeded Swede Sofia Arvidsson in Saturday's semi-finals.
"It was a very good match today as both of us played very well," Wozniacki, 22, told reporters.
"The difference at the end was that I could just keep my highest level up and I managed to win the most important points, especially at the beginning of the third set."
Arvidsson eased past seventh seed Maria Kirilenko 6-3 6-3, knocking out the last remaining Russian in both the men's and women's singles of the Moscow indoor event.
Kirilenko's exit was a blow to the organisers, who had hoped for bigger crowds at the weekend after the spacious Olympic arena was nearly empty for the first four days of the tournament. The attendance was slightly better on Friday.
The second semi-final will pit Australian top seed Samantha Stosur against fourth-seeded Serbian Ana Ivanovic.
Stosur dismissed unseeded Czech Klara Zakopalova 6-1 6-3 while former world number one Ivanovic was just as ruthless against 160th-ranked compatriot Vesna Dolonc 6-4 6-1.
"I expect a tough match against Ana," said Stosur, the 2011 U.S. Open champion. "You have to be ready for long rallies."
On the men's side, Malek Jaziri beat Czech Lukas Rosol 7-6 6-3 to become the first Tunisian player to reach an ATP World Tour semi-final.
Jaziri, who upset third seed Viktor Troicki in the second round on Wednesday, saved all seven of the break points he faced and converted one of his eight opportunities to claim victory in one hour 44 minutes.
"I'm really happy to reach the semi-finals here and if I'm lucky enough, why not make my first tour final?" said the world number 112, who will face second seed Andreas Seppi on Saturday.
Italy's Seppi thrashed eighth-seeded Japanese Tatsuma Ito 6-2 6-1 in less than an hour.
French qualifier Edouard Roger-Vasselin, who knocked out top seed Alexandr Dolgopolov on Thursday, could not repeat his heroics, going down to giant Croatian Ivo Karlovic 7-6 6-3.
Karlovic, one of the tallest players on the tour at 2.08m (6 feet 10 inches) who fired 23 aces against Roger-Vasselin, will face fourth-seeded Brazilian Thomaz Bellucci, who beat Poland's Jerzy Janowicz 6-4 7-6 in the last match of the day. (Editing by Alison Wildey)