PARIS: Russian top seed Elena Dementieva marched into the semi-finals of the WTA Paris Indoor Open on Friday by beating Germany's Andrea Petkovic 3-6, 6-4, 6-2.

The world number seven struggled to hit top form from the start, dropping the first set against the unseeded 22-year-old.

Petkovic fought hard in the second but the 28-year-old Russian's first serve was too strong and Dementieva went on to win in three sets for a last four match-up against unseeded American teenager Melanie Oudin.

Dementieva hailed Petkovic's determination and admitted her victory over her younger opponent was hard-fought.

"It was a tough one for me to win today."

"I wasn't quite sure what to expect at the beginning of the match as we had never played against each other before. I was impressed with how aggressive she (Petkovic) played," the Russian added.

Petkovic said she was pleased with her overall performance despite going out.

"I think that I started very well, Elena was a bit surprised," Petkovic said after the match.

"However against players like Elena, one moment can change the whole match and that is what happened today. I've got to learn a lot from this match but I will improve I think," she said in French.

On Thursday, the German revealed she wanted to set up her political party back home to represent young people.

That prompted a question on Friday from a journalist about her views on French president Nicolas Sarkozy.

Petkovic replied by describing the French head of state as "the little Napoleon."

"I don't have a very strong opinion of him because I have not read a lot about politics in France but I think that he is very active," she said in French.

Also Friday Italy's Flavia Pennetta made quick work of her compatriot Tathiana Garbin.

The number two seed and world number 12 took just 58 minutes to send her fellow Italian home, winning the match 6-1, 6-3 to book a semi-final clash with the Czech Republic's Lucie Safarova.

Safarova, an Australian Open quarter-finalist in 2007, knocked out Israeli Shahar Peer in straight sets 6-3, 6-0.

Peer, ranked number 22 in the world, struggled with Safarova's return of serve, who showed the same form that powered her to the final of this tournament three years ago.

"I was trying to stay focused on each point and each game from the beginning of the match on," the Czech said. "But of course in the end, I?m happy that it went so well."

Meanwhile Oudin, at 18 the tournament's youngest player, beat Hungary's Agnes Szavay in three sets.

Oudin dropped the first set 6-2 but showed composure beyond her years to come back and win the next two. The second set was closer, finishing 6-4. With Szavay visibly tiring, Oudin wrapped up the final set 6-2.

"I just kept fighting and I started playing some really good tennis and had a great third set," Oudin said.

The teenager told reporters that she expects "a really tough match" against Dementieva.