Ahly maintained the majority of the side that edged El Gaish in the league last time out, with Walter Bwalya the notable introduction.
Mosimane was given an early set-back when defender Yasser Ibrahim came up short inside ten minutes and had to make way for fullback Mahmoud Wahid.
Having lost their last group stage match, Ahly aimed for a quick start inside 14 minutes but Mohamed Magdy Afsha headed a cross from Ayman Ashraf wide.
The Cairo Red Devils were denied the lead seven minutes to the break when Amr El-Sulaya saw his shot cleared from the goal-line before Bwalya nestled the post on the follow-up.
Vita thus broke the deadlock in the final four minutes of the first half through a well-taken finish from Glody Lileipo after leaving Ashraf for dead.
Ahly targeted a strong start to the second half and nearly draw level from a sitter by Bwalya, but he couldn't profit.
It was his last outing inside the first ten minutes of the second stanza as he made way for Taher Mohamed with Mohamed Sherif also introduced for Hussein El Shahat.
The comeback from the champions came within 69 minutes after Sherif followed on a ball from Junior Ajayi before bustling the net.
It was two inside two minutes as Marwan Mohsen brought down a cross from Afsha for a composed finish from point-blank range.
As a victory loomed, Vita drew level from the spot through Ricky Tulengi following a coming-together inside the danger area to leave Ahly's qualification hopes from Group A in limbo.
