Moamen Zakaria scored after just three minutes for the record eight-time African champions at the Borg El Arab Stadium in Mediterranean city Alexandria.
But leading Wydad scorer Achraf Bencharki levelled on 16 minutes and dominant Ahly were unable to regain the lead before a crowd restricted to 50,000 for safety reasons.
Wydad host the return match today and are favoured to pocket the record $2.5 million (2.1 million euros) first prize given their home form in Africa this season.
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The Moroccan outfit won all six home matches en route to the final, including a 1-0 last-eight victory over defending champions Mamelodi Sundowns of South Africa.
Apart from the record purse, the African champions qualify for the even more lucrative FIFA Club World Cup in the United Arab Emirates during December.
One-touch passing down the left flank created the early chance for Zakaria, and his looping left-foot shot went over goalkeeper Zouheir Laaroubi into the corner.
Bencharki stunned the home crowd into silence when his glancing header off a pin-point Mohamed Ounajem cross flew into the far corner.