Pennetta, the fourth-worst ranked of any US Open women’s semi-finalist ever, will next face the winner of a later match between Belarus second seed Victoria Azarenka and Slovakia’s 48th-ranked Daniela Hantuchova.
Pennetta, who has not lost a set in the tournament and has dropped only 25 games in five matches, owns a 3-2 career edge against Hantuchova and has split two matches with two-time reigning Australian Open champion Azarenka.
Top-ranked defending champion Serena Williams and Chinese fifth seed Li Na will meet in Friday’s other semi-final at Arthur Ashe Stadium.
Williams, Li or Pennetta — all 31 — will become the oldest US Open women’s champion by winning Sunday’s final. “It’s amazing,” Pennetta said of her
win. “I’m really happy. I can’t believe it.”