Caleb Amankwah scored the only goal as the Ghana Premier League champions edged Elmina Sharks 1-0 at the Nduom Sports Complex.
The 23-year-old defender curled a superb freekick over the wall into the back of the net in the second half of extra-time.
The Phobians become the second club to reach the last four, joining Ashgold who beat Kintampo Top Talent FC earlier in the day.
The final four teams will be known after Sunday’s games. Kotoko must overcome Berekum Chelsea to be part while Medeama take on Attram DeVisser in Tarkwa.
The Semi-final encounters are pencilled for July 31 and August 1 with the two games taking place at Cape Coast Stadium.