ZESCO United were held 1-1 at home by Primeiro de Agosto in their opening Caf Champions League bout on Saturday.
Mabululu gave the hosts the lead in the ninth minute, but defender Clement Mwape equalised for the visitors seven minutes later to secure a valuable point in Luanda.
Agosto opened the scoring when Mabululu met Manuell Afonso’s fine cross, but they were unable to hold their lead and had no answer when Mwape turned home Thabani Kamusoko’s corner.
Christian Ngudikama could have added to the score for the Angolans following a fine dribble, while Jacob Banda was forced into an excellent stop to deny Afonso.