England's Laura Massaro beat defending champion Nicol David in five epic games to reach the US Open semi-finals.
Massaro rallied from two games down to overcome Malaysia's eight-time world champion 8-11 4-11 11-6 11-8 12-10 in a 71-minute match in Philadelphia.
The 31-year-old will take on Egypt's Omneya Abdel Kawy in the semi-finals.
Men's second seed Nick Matthew, 35, made just five errors as he beat Egypt's Fares Dessouki 11-6 11-2 11-7 to make the last four.
"I think that was maybe my best tactical performance of the week," said Matthew, the 2007 champion.
"I've made the final here a few times in the last few years but never got past that final hurdle so hopefully this is the year that I can change that."
Matthew will face Omar Mosaad for a place in the final after the Egyptian beat England's Daryl Selby 3-2.