Ellis' side won the 2022 edition of the tournament, beating Morocco 2-1 in the final in Morocco.
In 2024, they ended in fourth place with a loss to Ghana in the bronze medal match after a semi-final defeat to Nigeria.
They are in Group B in the competition set to kick off on Friday night, where they face Ivory Coast, Burkina Faso and Tanzania.
Ahead of the game, Ellis said on IOL: "We're obviously start off with Tanzania and we've always had tight games against them so we're not going to underestimate them, you underestimate a team at your own peril and the next thing you know you're chasing the game.
"So it's important to get a good start and set the tone for the rest of the tournament and after that we can focus on the main goal which is to qualify for the World Cup and then we take it from there."
South Africa open their Group B campaign against Tanzania on Monday. The four semi-finalists will secure automatic qualification for the 2027 FIFA Women's World Cup in Brazil.
"Pressure is a privilege, the minute you come into this team there's pressure but the team usually handles that well and the experience we've had having been here and done it before will help a lot especially for the six players that are coming into a WAFCON tournament for the first time," Ellis added.