The tie will be played at the iconic Prince Moulay Abdellah Stadium, where close to 70,000 fans are expected, the vast majority backing the Atlas Lions as they continue their pursuit of a first continental title in over 50 years.
Speaking ahead of the fixture, Onana acknowledged Morocco’s status as favourites but insisted Cameroon are prepared for the challenge despite the hostile atmosphere.
"I think we are the underdogs - this is their country, we have to acknowledge it. They've got quality players, but as for us, we've got our team spirit, because that's what's brought us this far in the competition."
Despite those factors, Onana insists the tie will ultimately be decided by which side gets it right tactically.
His Morocco counterpart Ismael Saibari addressed that very same element too, seeing it as the driving force behind the hunt to win AFCON.
"Of course it's important for our nation and the people, and also for ourselves to go and make history. We will give everything we can to bring joy to this country. Football is a big part of our country's identity."
Saibari ended off by saying he expects a high tempo game that might at times become a physical affair.