In the Setif exchange, the Dormaa-based club had a 1-0 first leg home advantage before being hit for four on the road to force a drop to the less prestigious Confederation Cup.
“We don’t know much about the Fosa Juniors but we have learnt our lesson from the Caf Champions League and we are going to take our chances," coach Yusif Abubakar told Graphic Sports.
"It will not just be sad, but a huge embarrassment that we would allow a team from an unknown football nation to take us out of the competition.
“We are not being complacent, but certainly we are wiser now and we have learnt how costly not taking the chances we create can be.
"We are not letting down our guards on Sunday.
"Gradually, the team is picking up more steadily and showing more toughness and character, that is how we want to be identified this season."
FA Cup holders Fosa are making their debut in a Caf inter-club championship.
They beat AS Port-Louis 2000 of Mauritius 3-0 on aggregate in the Confederation Cup first round to make the playoffs.