Pennetta reaches first-ever Grand Slam semi

Former top-10 star Flavia Pennetta secured a berth in her first-ever Grand Slam semifinal with a big win Wednesday at the U.S. Open.

The 31-year-old upset 10th-seeded fellow Italian Roberta Vinci 6-4, 6-1 on a sun-drenched day at the USTA Billie Jean King National Tennis Center. Pennetta ousted fourth-seeded compatriot Sara Errani in the second round here last week and has perhaps reestablished herself as Italy's best player.

Following a competitive opening set, Vinci appeared to give very little effort in the second, as the uneventful bout was over in 64 minutes at Ashe Stadium.

"I'm really happy. I cannot believe it," said an elated Pennetta, who has yet to drop a set at this Big Apple fortnight.

Pennetta improved to 5-4 lifetime against Vinci, including 2-0 at Grand Slam events.

The 30-year-old Vinci was playing in her second straight U.S. Open quarterfinal (0-2). She's never played in a major quarter outside of New York.

Vinci and Pennetta are two of five thirtysomethings in the quarterfinals here, equaling the most in the Open Era at any Grand Slam event.

Pennetta's semifinal opponent on Friday will be second-seeded former world No. 1 Victoria Azarenka, of Belarus, or former top-10 Slovak Daniela Hantuchova.

The world No. 83 Pennetta played in her fourth U.S. Open quarterfinal in her last five trips to Flushing. She missed last year's Open because of a right wrist injury.

This will mark Pennetta's first major semi in 41 Grand Slam events. She's never advanced beyond the fourth round at the Australian Open, French Open or Wimbledon.

The other semifinal will pit top-seeded Serena Williams against fifth-seeded Li Na, who was this year's Aussie Open runner-up and is a former French Open champ.

The 16-time Grand Slam titlist Williams is a four-time U.S. Open champion and two-time runner-up. She beat Azarenka in last year's finale in Flushing and captured the French Open back in June.

The 2013 U.S. Open champ will earn $2.6 million. The current world No. 1 Williams would claim an additional $1 million as a result of capturing the U.S. Open Series.