Ghanaian Isaac Mensah, in the 46th minute, scored the solitary goal of this challenge, which took place at the 11 de Novembro stadium, in Luanda.
With this victory, the 'oil companies' are now two points behind leader 1º de Agosto, four-time champion, trained by the Portuguese Paulo Duarte.
On Friday, Petro de Luanda will return to the scene to face Sagrada Esperança, in a match for the 15th matchday. In case of victory, Petro takes the lead of 'Girabola 2020/21'.
Das Faa, from Interclube, a team led by the Portuguese Ivo Campos, and Mabululu, from 1.º de Agosto, are the best scorers in the competition, with seven goals each.