In the Women's draw an Egyptian finalist is guaranteed after the trio of Nour El Sherbini, Raneem El Welily and Nouran Gohar came through to join the in-form Frenchwoman Camille Serme in the last four.
After stuttering early in the tournament Gohar secured an eye-catching 3-0 win over former World No.1 Laura Massaro courtesy of a dominant performance that saw her control proceedings from the start and leave Massaro powerless to halt the charge.
"In the first round I didn't think my shots were going well and I didn't feel like I was moving very well," said 19-year-old Gohar. "But I've stuck to the plan and been improving with each match.
"I tried to make sure I stayed positive. My mum was with me reminding me that I've trained very hard in the past few weeks.
"But even at 2-0 today I knew I had to stay fully focused because she can come back. She's so strong mentally, so I'm very happy to have come through."
Gohar will face defending champion El Welily while El Sherbini will face Serme, who extended her unbeaten run to 12 matches, after recording a seventh straight victory over eight-time World Champion Nicol David.
"I've watched Nicol since I was six years old and I've learnt a lot from her," said El Sherbini.
"She's always difficult to play against - she fights for everything and never gives up. It is always very tough and she brings the best out of me but I am happy that I am through."
Results - Quarter Finals: 2017 Women's Windy City Open
 Nour El Sherbini (EGY) bt  Nicol David (MAS) 3-1: 11-9, 6-11, 11-6, 11-4 (45m)
 Camille Serme (FRA) bt  Alison Waters (ENG) 3-1: 10-12, 11-6, 12-10, 11-4 (51m)
 Raneem El Welily (EGY) bt  Amanda Sobhy (USA) 3-1: 11-6, 11-7, 5-11, 11-5 (30m)
 Nouran Gohar (EGY) bt  Laura Massaro (ENG) 3-0: 11-7, 11-3, 11-5 (37m)
Draw - Semi-finals:
 Nour El Sherbini (EGY) v  Camille Serme (FRA)
 Raneem El Welily (EGY) v  Nouran Gohar (EGY)