Unseeded Angelique Kerber is through to the semi-finals of the US Open after defeating Flavia Pennetta in three sets.
In a match where both players struggled to hold serve, the German claimed the first set 6-4.
Number 26 seed Pennetta fought back to take the second 6-4, before Kerber sealed her place in the last four with a 6-3 third set victory.
The 23-year-old, who has never been beyond the third round of a Major before arriving at Flushing Meadows this year, will now face Australia's Sam Stosur for a place in the final.
