كتب : Ahmad Saied
Ittihad defender Osama Hamadi headed into his own net in the 20th minute as the packed Cairo International Stadium went wild.
The defending champions, who held Ittihad to a goalless draw in the first leg, will play Tunisian side Etoile Sahel in the final.
Ahli have crushed Etoile 3-0 on aggregate in the Champions League finals in 2005 and beat Tunisian club Sfaxien the 2006 final.
Motivated by huge support and good result in the first leg, Ahli started the game in an attacking style in a bid to score an early goal.
Star midfielder Mohamed Abou-Treika played behind strikers Flavio Amado and Emad Meteb with Gilberto and Mohamed Barakat launching raids from the wings,
Flavio could have scored the opener as early as the first minute when he scuffed a loose ball on the edge of the area but was too slow to slot it past the stranded goalkeeper.
Meteb, who has been dropped from the starting line-up recently, squandered the second chance in the seventh minute when he went one-on-one with Ittihad keeper Samir Aboud, but the Libyan goalie advanced to end the threat.
Gilberto dominated the left-hand side and swung several crosses into the area and despite Ahli players' failure to convert them Hamadi did the job well for the Egyptians.
He cut ahead of Meteb to clear Gilberto's right-footed cross but instead he sent it past his goalkeeper.
Ittihad tried to respond quickly but failed to threat Ahli keeper Essam Al-Hadari, who calmly foiled every Libyan attempt before the break.
Flavio almost doubled the lead a few minutes before the break but when a loose ball felt into his path inside the area but his shot was saved by Aboud.
The Angolan international continued his disappointing run after the break, slamming another wonderful Gilberto cross outside the frame of the goal.
Ahli coach Manuel Jose opted for a more conservative strategy midway through the second-half, fielding center-back Wael Gomaa for Abou-Treika.
Substitute Pierre Koulibaly missed a golden opportunity to fire Ittihad into the final seven minutes from time when he sent a low drive but the ball went just wide.
Koulibaly turned into a curse on his side a few minutes later when he received a red card for hitting Ahli's Ahmed Al-Sayed off the ball.
Watch Ahli's goal against Ittihad: