DR Congo striker Cedric Bakambu scored the winning goal for his team against Liberia.
DR Congo and Zimbabwe claimed two vital wins on Sunday to seal their places at the 2019 Africa Nations Cup in the last round of the qualifiers.
DR Congo were third of Group G ahead of the game and were in a must win situation when they faced second-placed Liberia to qualify for next summer's tournament that will be held in Egypt.
Cedric Makambu scored the only goal of the game as DR Congo pipped Liberia to finish second in the group with nine points, two ahead of their rivals.
Zimbabwe -- who only needed a draw -- consolidated their lead on top after beating DR Congo 2-0.
Khama Billiat, 21, and Knowledge Musona, 36, scored two first-half goals to seal smooth passage to the Egypt finals.
It will be Zimbabwe's fourth appearance in the Nations Cup and their second in a row. They were eliminated from the group stage in Gabon 2017.
(For more sports news and updates, follow Ahram Online Sports on Twitter at @AO_Sports and on Facebook at AhramOnlineSports.)