Bojan Krkic, Jose Manuel Rueda, Jeffren and Pedro wrapped up an easy win for the Blaugrana, while Hani Al-Egeizi scored Ahli's only goal.
Josep Guardiola fielded a star-less line-up keeping his big guns on the bench, much to the relief of the Red Devils, who were spanked by Celtic on Friday.
Despite that, the Barca youngsters dictated play as Ahli players looked nervous for long spells of the game against the Liga giants.
Krkic Deja Vu
After 16 minutes, Krkic, who scored on his debut against Ahli in April 2007, found the Egyptian giants' net once again when he ran rings around Ahmed Al-Sayed, before firing in from a difficult angle.
Barca remained in charge of the game for a while, but Ahli redeemed themselves midway through the first half and their efforts paid off in the 31st minute.
Defender Ahmed Ali applied an outstanding counter-attack move before beating the offside trap with a deft pass to Al-Egeizi, who rounded Jorquera to hit an empty net.
Four minutes later, Amir Abdul-Hamid denied a close-range header from Krkic, but the Ahli guardian could do nothing with Barca's next attack.
Four minutes from the break, Rueda feinted past Moataz Eno, before unleashing an unstoppable screamer from 25 yards into Abdul-Hamid's top left-corner.
Subs kill off game
Guardiola made a number of substitutions at half time including Yaya Toure, Victor Valdes and most importantly Lionel Messi.
Substitutes Messi, Pedro and Jeffren combined brilliantly and the latter easily tapped in the third 11 minutes after the interval as Ahli keeper Abdul-Hamid was injured in the process.
Consequently, youngster Ahmed Abdel-Monem came on and was beaten seven minutes after his introduction by a neat finish from Pedro.
However, the 21-year-old made a couple of fine saves to thwart Jeffren and Dalmau, denyin Barca a fifth goal.
Liberian striker Francis Doe replaced Al-Egeizi and came close to scoring a late consolation for Ahli, but his effort was blocked by Valdes.