MOSCOW, Russia - Serena Williams fended off a second set challenge and managed to advance past Nicole Vaidisova in straight sets at the Kremlin Cup, and will now be joined by three of Russia's best in the semifinals.

Williams and Vaidisova held tightly onto their service games throughout the first set except for the seventh game, where the American pounced and grabbed a break at 15, which was eventually all she needed to secure the one set lead. Things got far more complicated in the second set, as Vaidisova went up 5-3 and would have set point as Williams served at 5-6, but the former world No.1 hung tough, clinching a 64 76(7) win on her fourth match point in the second set tie-break.

Next up for the No.4-seeded Williams is No.2 seed Svetlana Kuznetsova, whom she played - and lost to - a week ago to this day in Stuttgart.

"I served really well today, and that was key," Williams said. "Svetlana is doing so well. She has moved up to No.2 in the world and she's now the No.1 Russian, which, trust me, means a lot, because there are a lot of Russians out there. I've got nothing to lose in tomorrow's match because she's ranked higher than I am.

"That's how I felt in Australia... every match, from Petrova to Jankovic to Shahar Peer, I felt like I didn't have anything to lose, and it got me the title, my eighth Grand Slam. I actually enjoy being in that position because I feel like I have no pressure and I play better. So it's cool."

Kuznetsova, who recently reached her third major final at the US Open, gave Williams a 63 63 drubbing in Stuttgart last week, and on Friday in Moscow won her quarterfinal match against Vera Dushevina in similar dominant style, 62 62.

"In Stuttgart she served really well, and I expect her to serve well again," added Williams. "She played like the No.2 player in the world. I'm very happy for her that she's playing so well. I'll just have to be tough. It'll be a good match."

"I played an unbelievable match against her last week," Kuznetsova declared. "I expect it to be very hard; hopefully I can play well again."

Kuznetsova is the No.1 seed at a Sony Ericsson WTA Tour event for the third time in her career. In both of her previous attempts as a top seed she has come away with the title, at the Tier III stop in Bali just over a year ago and at the Tier II in New Haven in August. This would be her biggest career title run as a top seed.

Rounding out the final four in the Russian capital are two more of the country's own, Elena Dementieva and Dinara Safina. Dementieva made her fifth straight Kremlin Cup semi with a 76(4) 62 win over Victoria Azarenka, while Safina beat another Russian, Vera Zvonareva, 62 36 63, to reach her second semifinal here, having come this far two years ago. The pair is 1-1 in completed matches.

Since it became a Tier I stop in 1997 this is the third year that a trio of Russians has featured in the final four of the draw. Dementieva is the only player to have been in all three of those trios (the other years were 2004 and last year).

Azarenka and Dushevina, who both bounced seeded players earlier in the week, were contesting their first ever Tier I quarterfinals.

Despite the singles loss, Azarenka still notched a victory in doubles on Friday, partnering Belarusian compatriot Tatiana Poutchek to dismiss Iveta Benesova and Galina Voskoboeva in the semifinals, 61 16 108. In Sunday's final, they will face the winner of Saturday's second semifinal between No.1 seeds Cara Black and Liezel Huber and No.3 seeds Safina and Elena Likhovtseva.