Wimbledon champion Maria Sharapova beat former world number one Venus Williams 6-3, 6-4 on Friday to reach the semi-finals of the Zurich Challenge.

Frequently putting Williams on the back foot in a battle of past and present Wimbledon winners, the 17-year-old Russian further underlined her country's domination of the women's game.

The world number seven was in almost constant control, combining fierce ground strokes and ferocious returns of serve to win in just 75 minutes.

"I was able to pick up my game when I needed to and force her to make some unforced errors," Sharapova said. "I thought I was dictating the match throughout and I'm definitely playing with a lot of confidence."

It was the Russian's 11th victory in a row, following on from tournament triumphs in Seoul and Tokyo.

Local favourite and 10th seed Patty Schnyder will contest Saturday's second semi-final against Australia's Alica Molik.

Schnyder, who won the Zurich title in 2002, came back from a set down on Friday to defeat Argentina's Paola Suarez 2-6, 6-3, 6-4.

Sharapova's win means she is almost certain to qualify for the end-of-season WTA Tour championships in Los Angeles next month which carry a one million dollar winner's prize.

Williams's chances of being in the draw are likely to depend on how she and fellow American Jennifer Capriati fare at next month's Philadelphia tournament.

"I just had a slow start today," Williams said. "I definitely feel I'm not at my best yet but it's just the little things that I still have to work on."

ALL-RUSSIAN CLASH

Sharapova, seeded fourth in Zurich, will now take on third seed Elena Dementieva in an all-Russian semi-final.

Dementieva advanced to the last four earlier on Friday with a 6-1, 5-7, 7-5 win over Japanese ninth seed Ai Sugiyama.

The world number five had looked on course for a convincing victory after easing through the opening set in 22 minutes.

But just as in Thursday's second round match against compatriot Elena Bovina, Dementieva seemed to lose her concentration in a second set strewn with unforced errors.

With both women staying close to the baseline, the third set was tightly contested.

Dementieva grabbed a decisive break in the penultimate game to reach the Zurich semi-finals for the first time in six attempts.

Dementieva will be looking to end something of a jinx against compatriot Sharapova.

The 22-year-old was a finalist at the French and U.S. Opens this year but was beaten on both occasions by Anastasia Myskina and Svetlana Kuznetsova respectively.

Dementieva has also lost to Russian opponents in three of her last five tournaments.