In a game played in the province of Huila, the goal was scored by Dago, in the 70th minute, after assisting Hossi.
The second leg will be played next Sunday, in Congolese territory.
For the same competition, the two-time champion Petro de Luanda, trained by the Portuguese Alexandre Santos, is exempt from the first phase, and should enter the scene between September and October, against the winner of the confrontation between Songo de Moçambique and Mambas do Eswatini.
For the second biggest competition on the African continent, at club level, the African Confederation Cup, Académica do Lobito beat La Passe FC, from the Seychelles Islands, by 2-1.
Tubarão, in the fifth minute, opened the scoring, while Monmae, minutes later, restored equality, and Jepson, in the 12th minute, scored the winning goal.
The second leg is played in a week's time in the Seychelles.
For the same competition, Sagrada Esperança, exempt from the first round, will face Belle Lumiere, from the Comoros Islands, in the second round of access to the group stage.
