Mosimane made four changes from the FIFA Club World Cup win on penalties against Palmeiras, as he recalled Kahraba, Junior Ajayi and Aliou Dieng while Mahmoud Wahid got a rare start at left-back.
The Red Devils were on the front foot early on as Mohamed Magdi Kafsha came close with a header in the sixth minute from the centre of the box that missed narrowly wide before Kahraba dragged a strike just wide from a similar position 10 minutes later.
Kahraba came close again to breaking the deadlock for the hosts just before the half-hour mark with a close range strike that was saved by goalkeeper Monged Abuzaid after a headed pass by Walter Bwalya.
After creating plenty of chances again after the break, Kafsha finally broke the deadlock for the Red Devils just before the hour-mark with a header in the centre of the box after a cross by Mohamed Hany.
Kahraba quickly doubled the lead for Mosimane's charges in the 63rd minute with a finish into the bottom corner after a through ball by Ajayi.
Bwalya put the game to bed for Al Ahly in the last 19 minutes with a left-footed strike of his own, as the Red Devils moved top of Group A with a convincing win.