كتب : وكالات
The only goal of the game was scored by captain Sherif Reda, who bundled in a close-range effort after the break to give his side their second win of the season.
It is Ahli's third defeat in five games; a poor run that the African giants had not endured in several years.
The victory is also the first-ever for Hurghada side Gouna since their promotion to top division in 2009.
Gouna, who are managed by former Ahli coach Reiner Zobel, move off the bottom of Group A with seven points.
Ahli are second after Arab Contractors, who will meet Dakhlia on Sunday.
Ahli will face a tougher task in their next game as they take on Tunisia's Sfaxien for the African Super Cup title on Thursday.
VIDEOS
Reda scores winner on 52 minutes.