The second edition sees the tournament expanded to 16 countries from eight and Sudan are considered one of the teams who could trouble title favourites and defending champions DR Congo.
Shock 2010 Club World Cup runners-up TP Mazembe form the backbone of the DR Congo squad with 11 players, including goalkeeper Muteba Kidiaba -- famous for his bottom-bouncing celebrations -- and consistent scorer Dioko Kaluyituka.
Gabon were rated outsiders in Group A which includes Algeria and Uganda -- who meet Saturday at the same Khartoum stadium where Sudan won -- and fell to a Mudather Eltaib goal 27 minutes into the first half.
Midfielder Eltaib is an experienced African campaigner with the national team and Omdurman club Al-Hilal and nicknamed 'Careca' after the famed Brazil striker of several decades ago.
Nations Championship teams like Sudan can field a full-strength national team because they have no foreign-based stars, while virtually all the top Gabonese footballers compete abroad and are ineligible.
There will also be two Group B fixtures Saturday in Wad Medani south of Khartoum with Ghana, runners-up two years ago, facing South Africa before Zimbabwe confront shock qualifiers Niger.