Uganda, Mali, Namibia, and Ethiopia returned home with aggregate advantages as Mauritania and Zambia forced away draws in day One of the 2020 African Nations Championship (CHAN) qualifying.
Moussa Kone put 2016 runners-up Mali ahead within two minutes in Guinea-Bissau and added a second before half-time.
Issiaka Samake and Dusse Kodjo netted inside six minutes midway through the second half to complete a 4-0 victory that virtually assures Mali of a place in the final qualifying round.
Mauritania is the likely opponents of Mali during September and October after forcing a 0-0 draw away to debutants Cape Verde in Praia.
Kambindu hit a brace during the second half as Namibia avenged an away defeat by Comoros in 2018 qualifying with a 2-0 victory in Moroni.
If Namibia completes the aggregate victory next weekend, they will face Madagascar or Mozambique for a place at the 2020 tournament in Cameroon.
Goals from Patrick Kaddu, Mustafa Kizza and Taddeo Lwanga earned Uganda a 3-1 win over Somalia, who staged their home match in neighboring Djibouti for security reasons.
Kaddu and Lwanga were part of the Uganda squad that reached the last 16 at the Africa Cup of Nations in Egypt this month before losing narrowly to eventual runners-up Senegal.
Ethiopia, the original 2020 hosts who were replaced by Cameroon after falling behind with preparations for the biennial 16-team tournament, edged Djibouti 1-0 in Djibouti City.
It took the Ethiopians 76 minutes to break down a stubborn home side with Aschalew Tamene snatching the match-winner.
Botswana 0-0 Zambia
Burundi 2-0 South Sudan