The hosts clearly lacked the necessary firepower to pull off a victory over their opponents, who were much better than expected.
Egypt coach Hassan Shehata deployed a 4-4-2 formation, which is quite unsual for the Pharaohs.
The Master also played inexperienced strikers Ahmed Ali and Ahmed Mekki after he left out key figures, such as Amr Zaki and Emad Meteb.
From Sierra Leone, Mohamed Bangura was arguably the best performer throughout the game.
Now Egypt are in Group G third place with one point, while Sierra Leone lie second.
South Africa, who beat Niger 2-0 on Saturday, are the leaders on three points.
Pressure
Visitors Sierra Leone seemed to be brave right from the beginning and even tried to pile up pressure upfront.
They carved out a number of chances in the first half but didn't genuinely threaten goalie Essam Al-Hadari.
Egypt's first scoring opportunity fell to Geddo when a Sayed Moawad cross picked him out unmarked, but his header went wide.
Abou-Treika tried to open the scoring afterwards with a precise low free kick that was punched away by the custodian.
Minutes later, the veteran playmaker released a powerful shot that stung the palms of the keeper before hitting the crossbar and going wide.
Egypt took the upper hand midway through the first half when their opponents eased off a bit, and tightened their grip on the game few minutes before the break.
Ahmed Elmohamady tried his luck from inside the area only to see his volley go past the post.
Late in the first period, the Sunderland right-sided midfielder sent a through to Abou-Treika, who feinted past the keeper before his cut-back was wastefully intercepted.
Control
For a while after the restart, the seven-time African champions remained in control whereas Sierra Leone tried to maintain a sturdy defense.
However, the away side rounded off a counter attack to take the lead on 57 minutes, thanks to sloppy defending from Ahmed Hassan and Wael Gomaa.
Sierra Leone did not enjoy their lead for long as Mahmoud Fathallah equalized three minutes later when he headed home an inch-perfect cross from Abou-Treika.
The match's tempo notably stepped up in the last 30 minutes of the match, with both sides looking for a winner.
Abou-Treika squandered a late chance when he was set up by Geddo, but his close-range effort went agonizingly wide of the mark.