Sixth-seeded Dinara Safina overpowered No. 16 Flavia Pennetta 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. The Russian 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.

“She was playing unbelievable, you know,” said Pennetta, from Italy. “She didn’t give me a lot of chance.”

Now comes a much harder assignment for Safina: trying to beat Venus or Serena Williams.

“It’s going to be a big match. You know, they’re both playing good,” Safina said. “I just want to focus again on myself and to give my 100 percent and see who’s going to be stronger.”

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.

She was asked which sister she would rather meet.

“I don’t care,” Safina said.

Yesterday’s schedule also included two men’s quarterfinals. No. 6 Andy Murray of Britain reached his first Grand Slam semifinal by beating no. 17 Juan Martin del Potro of Argentina 7-6 (2), 7-6 (1), 4-6, 7-5 in a match that lasted nearly four hours and delayed the start of Williams vs. Williams.

Murray, who ended del Potro’s 23-match winning streak, clinched a rise to No. 4 in the rankings, matching the highest spot ever for a British man. Neither he nor del Potro played particularly well — each made far more unforced errors than winners — but Murray’s biggest complaint was when his request to have the overhead video boards shut off during points was denied.