Liverpool star Sadio Mane scored the winner for Senegal against Guinea-Bissau.
The 82nd minute goal from Mane was enough to give Senegal all the points.
They now have 12 from their four group matches, and have qualified for the 2021 Africa Cup of Nations.
Senegal are the top ranked nation in Africa and will be hoping to win the trophy in January 2022.
The competition was slated to take place next year, but has been pushed forward due to COVID-19 schedule changes.
Cameroon are the only other team to have booked qualification so far.