Cameroon became the third team to qualify for the AFCON 2017 beside host Gabon thanks to a lone goal victory over Mauritania on Friday in Nouakchott.
The Indomitable Lions join Algeria, Morocco and host Gabon to confirm their place for the 2017 AFCON.
Midfielder Edgar Salli scored the only goal of the mouth on 29 minutes to settle matters.
Cameroon are destined to top the group with 11 points so far, four more than Mauritania. South Africa has three points with Gambia at the bottom with two points.
Gambia host South Africa on Saturday, 4 June 2016 in Bakau.