Famara Diedhou scored a hat-trick for the Teranga Lions on 22, 51 and 84 minutes while Peter Shalulile scored Namibia's consolation goal.
With two matches to spare, Senegal have now secured the top spot with 12 points eight ahead of their closest rivals Namibia and Togo, who have each four points, while Congo are bottom with 2 points.
They managed to win their first four games easily as they defeated Togo (2-0) in the first round, and Congo (3-1) in the second round, then smashed Namibia in the third and fourth rounds (4-1), (3-1).
In Group I, Morocco maintained their perfect record after beating Guinea 4-1 to go top with 12 points and secure their passage to the final phase of the qualifiers. They are out of reach for Guinea-Bissau (4 points), Guinea (3 points) and Sudan (2 points).
Ayoub El Kaabi opened the scoring in the 21st minute then Selim Amallah netted twice on 42 and 65 minutes but it was Sofiane Boufal who had the last word in the 86th minute. Mamadou Kane scored early in the game but it was no more than a consolation goal.
Also on Tuesday Ghana took a step closer to qualify for the playoffs as they defeated Zimbabwe 1-0 courtesey to a goal from Thomas Partey, reaching the ninth point in group G which also has South Africa who have seven points, Ethiopia three points, and Zimbabwe the bottom of the group with a solo point.
(For more sports news and updates, follow Ahram Online Sports on Twitter at @AO_Sports and on Facebook at AhramOnlineSports.)