By Jim Slater
Italy's Flavia Pennetta has shocked two-time Wimbledon champion and Czech fifth seed Petra Kvitova 4-6 6-4 6-2 to reach her second US Open semi-final.
Pennetta, who ended Sam Stosur's tournament in the fourth round, will face the winner of the clash between two-time Australian Open champion Victoria Azarenka and Romanian second seed Simona Halep for a place in Saturday's final.
"I'm really happy right now," Pennetta said.
"I was just trying to fight every ball, running and push everything I can.
"I didn't think to get through this match. In the second set I was playing and playing, it was unbelievable."
World No.1 Serena Williams, who holds all four major titles and seeks a calendar Grand Slam, will face Italy's 43rd-ranked Roberta Vinci in the other semi-final.
Williams is chasing the first calendar Grand Slam since Steffi Graf in 1988 and trying to match Graf's Open Era career record of 22 Slam singles titles, two shy of Margaret Court's all-time record.
AFP