Mosimane made two changes from the win over Al Merrikh, which saw Ramy Rabia withdrawn for Yasser Ibrahim and Hamdi Fathi restored for Amr Al-Sulaya, while Fagrie Lakay lead the line for Pyramids.
Ahly missed a big chance in the first ten minutes when from a tight angle Mohamed Magdy Afsha volleyed a cross right of the area from Rabia against the post.
Ehab Galal's men were on the receiving end of a clear chance minutes thereafter through Ebrahim Adel from poor defending by Ahly, but he steered wide.
The Cairo Red Devils shrugged off their slow end to the first half and grabbed the lead minutes into the restart through a smart finish from Afsha with the visitors caught out at the back.
Although, the home side's lead were quickly under threat from a promising free-kick by Abdallah El Said but Ahly goalkeeper Mohamed El Shenawy headed the call and smothered.
El Said was at the heart of another move for Pyramids minutes later when he worked an angle and fired a teasing shot against the upright.
South African international Percy Tau, who featured from the get go, was withdrawn in the last 20 minutes and replaced by Hussein El Shahat with Ayman Ashraf also introduced.
Then, minutes at the other end Lakay failed to bring the visitors level from a clear chance and a poor ball by fullback Ali Maaloul.
However, Ahly made the points safe in the last four minutes courtesy of a stunning finish from Al-Sulaya with the visitors once again failing to manage their lines.
The host bagged a third in added time after Mohamed Sherif capitalised on poor defensive communication to find the net and see Ahly go top of the table ahead of the self-same Pyramids.