* Wozniacki battles to beat Arvidsson
* Seppi to face Bellucci in men's final (adds Bellucci quote)
MOSCOW, Oct 20 (Reuters) - Top seed Samantha Stosur reached her first final in eight months with a comeback 2-6 6-3 6-2 win over fourth-seeded Serbian Ana Ivanovic in the Kremlin Cup semi-finals on Saturday.
The Australian will face another former world number one Caroline Wozniacki in Sunday's final after the Danish third seed beat unseeded Swede Sofia Arvidsson 6-3 6-7 6-4 in the first semi-final at the Olympic indoor arena.
Italian second seed Andreas Seppi, who is having his best season in 2012, will meet fourth-seeded Brazilian Thomaz Bellucci in the men's final on Sunday.
After splitting the first two sets, 2011 U.S. Open champion Stosur broke Ivanovic in the fifth game for a 3-2 lead after the Serbian missed an easy volley on break point.
Ivanovic took a medical break after falling behind but looked a shadow of her former self after coming back on court as Stosur reeled off the next three games for an easy victory.
"Ana played a very good first set, forcing me on the defensive," Stosur, who lost to world number one Victoria Azarenka in her last final in Doha in February, told reporters.
"In the second set I think I started serving a lot better and I was more aggressive on the returns. That was the key."
Ivanovic said once she felt a twinge in her side her level of play dropped. "I felt something in my hip. I tried to shake it off but it got gradually worse," she said.
Wozniacki had a much tougher time against her Scandinavian rival. She served for the match at 6-5 in the second set but 46th-ranked Arvidsson battled back to force a tiebreak.
In the third set, the Dane again served for the match after pulling ahead 5-3 and missed her chance on her serve but she finally ended Arvidsson's resistance in the next game.
World number 11 Wozniacki, looking for her second WTA title of the season after winning the Korea Open last month, blamed the slow surface for her inability to finish the match.
"It was very tough to finish off the point on this surface, especially because we know each other so well," she said.
"I had to raise my game in order to win today."
On the men's side world number 25 Seppi took just 79 minutes to dispose of Malek Jaziri, thrashing the first Tunisian player to reach the last four on the ATP Tour 6-3 6-1, while Bellucci beat giant Croatian Ivo Karlovic 6-7 6-4 6-4.
A tired-looking Karlovic, one of the tallest players on the tour at 2.08 metres and with a booming serve, doubled faulted to hand victory to the 41st-ranked Brazilian.
"For me it's very special to be playing in this final," said Bellucci, whose four previous finals had been played on clay.
"But it'll be a completely different match tomorrow, with lots of long rallies," added the 24-year-old three-times tour winner. (Reporting by Gennady Fyodorov, Editing by Tom Pilcher)