Ceramica Cleopatra moved ahead against Al Ahly on Tuesday night after Fakhri Lakay scored in the 40th minute.
The goal came from a powerful effort that goalkeeper Mostafa Shobier failed to handle cleanly, with the ball crossing the line to hand Ceramica the lead before the break.
The match was played at المقاولون العرب Stadium in the opening round of the Nile League title phase, a fixture carrying major weight in the race at the top.
Al Ahly were left needing a response in the second half as the game marked the start of a decisive domestic stretch.