Dementieva, who has struggled with injuries in 2010 and was eliminated on Thursday from reaching the semifinals, made her announcement in a tearful ceremony surrounded by other players. The 29-year-old Russian ended her 12-year career, which included two Grand Slam final appearances and an Olympic gold in Beijing, with a 6-4, 6-2 loss to Schiavone.

"It is so emotional. It is so hard to say goodbye. I am going to miss you so much," Dementieva said.

Looking at her mom Vera in the stands, Dementieva said: "My mom was very supportive and inspiring. She was always there for me. It is emotional for her as well. I love you mom." Schiavone was among the players on hand to watch the ceremony. Dementieva, who beat Sam Stosur of Australia on Thursday, had no chance of advancing to the semifinals because of earlier losses in her group.

Schiavone's consistent returns and net play forced Dementieva into hitting returns long and wide, giving the Italian an early lead. But unlike her two previous matches when she couldn't maintain early leads, Schiavone refused to let Dementieva back into the match. She repeatedly broke the Russian in the second set and at one point won 10 of 15 games. Schiavone also forced Dementieva to commit 28 unforced errors in the match.

"I played a little bit better and was little bit more focused and confident than Elena," Schiavone said after the match.

Fourth-ranked Kim Clijsters takes on second-ranked Vera Zvonareva in the next match, which will determine the matchups for Saturday's semifinals. The other semifinalists are top-ranked Caroline Wozniacki and Stosur.

Clijsters beaten Later, Vera Zvonareva ended Kim Clijsters' nine-match winning streak 6-4, 7-5 and secured the year-end No. 2 ranking.

Zvonareva, yet to drop a set after three group matches in the elite event, ensured she will play No. 1 Caroline Wozniacki in the semifinals on Saturday. Clijsters will face Sam Stosur in the other semi.

Zvonareva, who lost to Clijsters 6-1, 6-2 in the US Open final, used a strong net presence and powerful backhand to beat the Belgian for third time since Clijsters came out of retirement last year.

The first set went back and forth until Zvonareva's powerful return was netted by Clijsters. Clijsters jumped out to 3-1 in the second but couldn't hold on.

In Montpellier, France, sixth-seeded Albert Montanes of Spain rallied from a set and break down to beat top-seeded Nikolay Davydenko 3-6, 7-6 (3), 7-6 (4) in the quarterfinals of the Open Sud de France on Friday.

Montanes won on his third match point when Davydenko's weak backhand return hit the net. The Spaniard will play either fourth-seeded Ivan Ljubicic or Jarkko Nieminen in his first career indoor semifinal.

"It was a very hard game and I was fortunate enough to be able to break back in the second set," Montanes said.

"It's my first semifinal indoors and everything is going well for me. This gives me a lot of confidence for the rest of the tournament." Third-seeded Gael Monfils also advanced to the last four after beating No. 5 John Isner of the United States 3-6, 6-4, 6-4. Isner had 12 aces in the match to pass 1,000 for the season.

Monfils plays either No. 2 Jo-Wilfried Tsonga or Gilles Simon in the semis, guaranteeing a French finalist.

In St. Petersburg, Mikhail Kukushkin of Kazakhstan and Illya Marchenko of Ukraine earned their second career semifinal appearances at the St. Petersburg Open on Friday, a year after their first.

Both Marchenko and Kukushkin achieved their first semis on tour 12 months ago in Moscow as qualifiers.

This time, the unheralded duo have surprised the field as direct entries.

Kukushkin beat his second seed of the week in third-seeded Janko Tipsarevic of Serbia 7-5, 3-6, 6-4, while Marchenko ousted Benjamin Becker of Germany 6-4, 2-6, 6-2.

The 88th-ranked Kukushkin constantly dragged Tipsarevic into long rallies and wore him down.

Facing set point in the 12th game of the first set, Tipsarevic netted a forehand to end a 31-shot rally and lose the set.

Tipsarevic then won four games in a raw in the second to level the match, and jumped to 4-2 in the decider. But Kukushkin broke back with a lucky net cord in the seventh game, made another break in the ninth, and served the winner on his second match point.

"It was a tough match and Janko served hard today," said Kukushkin. "It was tough to get a chance on receiving but I was lucky to do it at 6-5 in the first set. And I was really lucky to have a net cord on a break point in the third set to break back and turn the match my way." Tipsarevic served 10 aces but converted only three of 11 break chances.

In Vienna, defending champion Jurgen Melzer reached the semifinals of the Bank Austria Trophy without playing after Philipp Kohlschreiber pulled out with a right adductor strain shortly before their quarterfinal on Friday.

The top-seeded Melzer, who was 0-3 in career matches against the German, next plays third-seeded Nicolas Almagro of Spain, who defeated No. 8 Juan Ignacio Chela of Argentina 7-5, 3-6, 6-3.

Almagro, who won two clay-court events over the summer, had nine aces and broke Chela four times to advance to his first hard-court semifinal this season.

Andreas Haider-Maurer joined fellow Austrian Melzer in the semifinals after upsetting last year's finalist and second-seeded Marin Cilic of Croatia 7-6 (1), 6-4.

Melzer said he was disappointed that he didn't have to compete to reach his fifth semifinal of the season.

"It's a pity, I'd loved to play," said the French Open semifinalist, who is ranked a career-high 12th. "I would like to show on court who's the best." Kohlschreiber's injury stemmed from a doubles match with fellow German Christopher Kas on Thursday.

"I made a wrong move and unfortunately things got worse overnight," the seventh-seeded Kohlschreiber said.

"Doctors told me not to play so I had no other choice." Haider-Maurer continued his remarkable run at the tournament by eliminating the 14th-ranked Cilic.

The 157th-ranked Austrian, who has never reached the quarterfinals of an ATP event before, lost in qualifying but entered the main draw after fifth-seeded Ernests Gulbis pulled out for personal reasons and then defeated both Thomas Muster and Andreas Seppi.

"A dream comes true," Haider-Maurer said. "I didn't believe before the match that I could win it." Cilic, who won two ATP events this season, had an early break and was 4-2 up in the opening set but produced a series of forehand errors as he started to lose control of the game.

Haider-Maurer leveled at 4-4, comfortably won the tiebreaker and managed a decisive break in the opening game of the second set.

The Austrian plays fourth-seeded Marcos Baghdatis or Michael Berrer in Saturday's semifinals.