Despite some struggles with her serve, the No. 1 seed defeated Dementieva 6-3, 6-4 to set up a clash with another compatriot, fourth-seeded Nadia Petrova, a 6-7 (3/7), 6-4, 6-1 winner over Virginie Razzano of France.

After Dementieva gave away the first set with two double faults on the last two points, Sharapova raced to a 4-1 lead in the second.

She had a break point in the sixth game but failed to convert and Dementieva battled back to knot the set at 4-4.

"Four-four is never easy, especially when you're up 4-1 and you have a break point," said Sharapova, who finally captured the match on her third match point. "The good thing about the end was that I didn't get frustrated. I just kept going. She definitely raised her level."

Second-seeded Jelena Jankovic and No. 3 Ana Ivanovic set up an all-Serbian semi-final.

Jankovic, runner-up to Dementieva here last year, emerged with a 6-4, 6-7 (5/7), 6-2 victory after a chaotic encounter with 18-year-old Victoria Azarenko of Belarus.

Jankovic, whose ranking has climbed to No. 3 in the world as she won four titles this year, found incorrect score calls by the chair umpire and restless spectators a distraction in a match in which she was already struggling.

"It was a circus," said Jankovic, who nevertheless admitted her biggest problem was her own inconsistency.

"I'm not on my game. I don't have a rhythm," she said. "But I made it. It's not the greatest match from my side, but I got the win."

French Open runner-up Ivanovic defeated Russian Maria Kirilenko 6-4, 6-4.

Kirilenko started strong and led 4-1 in the first set when she had on-court treatment for blisters on her fight foot.

Ivanovic won the next seven games, taking the first set and going up 2-0 in the second.

"I had some time to think about my game when she took a medical timeout," Ivanovic said. "I decided I needed to be more aggressive and it worked well for me."

It wasn't all smooth sailing, however. Leading 5-2 in the second set Ivanovic was broken, but managed to hold on for the victory.

Ivanovic, ranked fifth in the world, said she looked forward to meeting Jankovic, but Jankovic didn't echo that sentiment.

"I don't really think 'Oh, I'm playing a Serbian,'" Jankovic said. "It's just another player on the other side of the net."

Ivanovic has won four of their five WTA meetings, the exception coming in the quarterfinals here last year.

The two compatriots have conflicting memories of earlier encounters.

Ivanovic recalled playing Jankovic in a junior tournament in a converted swimming pool in Belgrade, when she was proud of taking one game from the player three years her senior.

Jankovic had no memory of it.

"She was probably confusing me with some other girl. She was actually the better player when we were younger," Jankovic said.