Aliou Dieng had the first notable shot after seven minutes but it was saved by the El Harby goalkeeper.
Al Ahly’s Kahraba had good chance from a tight angle but his volley went over the bar after 18 minutes.
Mosimane’s side received a penalty after 38 minutes when Marwan Mohsen was brought down by the opposition keeper, with Ali Maaloul converting the following spot-kick.
The home side had a chance to score in the third minute of injury time before the break but Mamadou Niass’ shot was saved.
However, nine minutes into the second half El Harby equalised through Mohamed Tarek who put the ball past Ali Lofty in the Al Ahly goal.
Mosimane responded by introducing Mohamed Sherif four minutes later but it was the home side who scored in the 64th minute from a counter, with Mostafa El Badry putting the ball past Lofty.
Al Ahly increased the pressure but it took until the 80th minute for them to have a good chance, when Marwan Mohsen headed the ball over the cross bar from close range.
Hussein El Shahat scored the much-celebrated 2-2 in the 85th minute with a shot in the far corner. Walter Bwalya netted Al Ahly’s third in the third minute of injury time with header.
The victory saw Al Ahly close their gap to log leaders Zamalek to six points with two games in hand.
