Banyana will take on the Black Queens in their Group C match at 18:00 at the Honneur Stadium in Morocco.
Ellis says they know it will be a challenging match, but a victory will be crucial.
"Both in 2018 and in 2022, we had two great opening results that really set the tone for the rest of the tournament. We know Ghana did not qualify for the 2022 edition, but they are a powerhouse on this continent, and we are expecting a proper challenge," said the award-winning coach.
The women's tournament was supposed to take place in 2024 but was postponed due to other events, including the Olympics.
Ellis says even though this gave the team more time to prepare, she believes that women's football should be taken more seriously.
"To be honest, sometimes women's football is not taken seriously. I don't think the organisers were brave enough to host the tournament in 2024. It's too easy to just shift a women's tournament, but we have adjusted accordingly and we are raring to go."
Banyana lifted the WAFCON trophy in 2022 with Hildah Magaia scoring a brace in the final against Morocco.
Ellis says they are not putting themselves under pressure as defending champions, but they are focused on playing like contenders like any other team.
Asked if she is bothered by African media reporting more on the other teams, the 62-year-old says they have worked too hard as a team to care about small things.