The Angolan winger delivered a superb set-piece onto the post as the two sides played out a draw.
Liverpool forward Mohamed Salah and Etihad counterpart Omar Marmoush watched from the bench as Group B winners Egypt were held to a draw with Angola at the Afcon 2025.
The seven-time champions, having clinched top spot, deployed an entirely changed starting XI and lacked a cutting edge in Agadir.
Angola, who needed a victory to keep their hopes alive, will now endure an anxious period to see if their solitary draw is enough to qualify for the knockout stage as one of the four best-placed third-place teams.
Several other nations are assured of at least third place in their pools, all having three points.
Attacker Fredy rattled the woodwork for Angola early in the second half, while Egypt's substitute – one of three players introduced by the Pharaohs – stung goalkeeper Hugo Marques' fingertips with a shot from inside the box.
Salah and Marmoush had previously found the net in comeback wins over Zimbabwe and South Africa, respectively.
Egypt will remain in Agadir to face a third-placed team next Monday, with their next rival to be confirmed after the preliminary round concludes on Wednesday.
In the other Group B closer, South Africa's 3-2 win over Zimbabwe sent Bafana Bafana into the next round, putting Angola on the outside looking in.
The Liverpool star watched Egypt draw a blank in an Afcon match for the first time since the 2021 tournament decider.
With top spot wrapped up, Egypt coach Hossam Hassan might have hoped for a more impressive display from his second string.
The striker, who netted four goals at the 2023 finals, created an early chance for Hossam Abdelmaguid, but the defender looped his header over the target.
Angola, making seven changes themselves, nearly went ahead when Chico Banza combined with Mabululu before dragging a shot wide.
The first half passed without a shot on target, although Fredy caused goalkeeper Mostafa Shobeir into action with a powerful long-range strike.
The Angolan captain was the most dangerous source, watching a set-piece elude the goalkeeper but clatter against the woodwork.
At the other end, Salah Mohsen was stunned after nearly prodding in a cross, only for the goal to be flagged offside.
Late efforts from M'Bala Nzola and Hamdi Fathy failed to break the deadlock, ensuring the match finished scoreless.
For Angola, last-eight participants in 2023, their disjointed showings in Morocco will lead to scrutiny about their mid-tournament managerial change.