NEW YORK — Sixth-seeded Dinara Safina of Russia overpowered No. 16 Flavia Pennetta of Italy 6-2, 6-3 in the U.S. Open quarterfinals Wednesday, earning the right to play one of the Williams sisters next.

Safina, the sister of 2000 U.S. Open men's champion Marat Safin, reached her first semifinal at Flushing Meadows. She has won 37 of her past 41 matches and made it to the finals at six of her previous seven events.

"I'm getting closer to reaching the same thing as my brother," Safina said.

The French Open runner-up and Beijing Olympics silver medalist compiled a 25-13 edge in winners against Pennetta and only was broken once.

Now comes a much harder assignment: trying to beat Venus or Serena Williams. The siblings, both two-time Open champions, were to face each other in the last women's quarterfinal Wednesday night, their 17th matchup as professionals.

Safina is 1-3 against Serena and never has faced Venus. Which would she rather meet?

"I don't care," Safina said.

Wednesday's schedule also included the first two men's quarterfinals, with No. 6 Andy Murray and No. 17 Juan Martin del Potro meeting in the afternoon, and No. 1 Rafael Nadal taking on unseeded American Mardy Fish at night, after Williams vs. Williams.

The sisters headed into that match 8-8 in all-Williams encounters, 5-5 at Grand Slam tournaments. Seven of those came in Grand Slam finals, including at Wimbledon in July, when Venus beat Serena in straight sets for her fifth championship at the All England Club.

Back when they were ranked Nos. 1 and 2, the siblings only could meet in tournament finals. But because of injuries, inactivity and inconsistency, they dropped in the rankings, and now it's the luck of the draw that determines at which stage they potentially meet.

At the U.S. Open, they wound up in the same section of the bracket, so what many might consider the two top players at the moment were forced to meet in the round of eight.

Serena has won eight major titles, and Venus has won seven — and none of the other quarterfinalists owns a single such prize. Before this tournament, Venus had reached the quarterfinals at 28 majors, and Serena at 23, while the six other women to reach that stage this time had made a combined total of 22 previous Grand Slam quarterfinal appearances.

For Pennetta, this was her first career major quarterfinal — and it showed, right from the start against Safina.

Pennetta came to the U.S. Open with a 21-22 career record in Grand Slam tournaments and a 1-4 mark at Flushing Meadows. She dropped her first service game Wednesday, misjudging an overhead to set up a break point, then flubbing a forehand to end a 15-stroke exchange.

That was part of Safina's run to leads of 3-0 and 4-1. When Pennetta sailed yet another groundstroke long while serving down 5-2, the Russian earned another break and owned the first set.

Safina's one real blip came when she was broken at love to fall behind 2-0 in the second set, as Pennetta smacked a backhand return winner on an 83 mph second serve. But Safina broke right back, then broke again for a 5-2 lead.

At the start of the U.S. Open, Safina was one of six women with a chance to be ranked No. 1 at the end of the tournament.

That included current No. 1 Ana Ivanovic, who was upset in the second round. But by virtue of No. 2 Jelena Jankovic making the semifinals, Ivanovic is assured of dropping from No. 1.

Jankovic will face No. 5 Elena Dementieva in the other women's semifinal. They advanced with victories Tuesday.