Cameroon advanced to the final after beating Zambia, while South Africa saw off Uganda in their semi-final tie.
Jermaine Seoposenwe went close to giving Banyana the lead after 12 minutes but she failed to slot home from close range, with goalkeeper Ngo Fiore collecting with ease.
Cameroon were nearly gifted the opening goal after a defensive error by Kholosa Biyana in the box, but they failed to test Kaylin Swart from close range after 28 minutes.
Refiloe Jane eventually handed Banyana the lead in the 43rd minute with a cracking strike from distance. Her second goal in as many games.
The Cameroonians managed to restore parity in the second half thanks to a strike from Mbeleck in the 63rd minute.
Desiree Ellis' charges continued to carve out chances but the likes of Thembi Kgatlana and Ramalepe failed to convert.
However, Banyana snatched victory in second-half stoppage time with thanks to Jane's second goal of the tournament, as the South Africans defended their title.