The Carthage Eagles of Tunisia topped the group with superior goals despite finishing on five points apiece with Guinea, who finished in second place. Nigeria had four points and Niger at the bottom with one point.
The striker who was adjudged the most valuable player of the match tucked home a cross from Aboubacar Sylla on the stroke of half time, for what turned out to be the goal that separated both sides.
The hotly contested game saw few chances with Guinea starting on a promising note only for Nigeria to come in the picture shortly after. The first half recorded a handful of chances from either side until Sankhon scored just before the interval.
Nigeria coach Sunday Oliseh introduced striker Chisom Chikatara for Paul Odeh upon recess and the former, who had scored four goals from the previous two games, made his presence almost felt with surging runs upfront.
Guinea goalie Abdoul Aziz Keita pulled the save of the day seven minutes from time by pushing out substitute Bright Uchechukwu’s thunderbolt for a corner and effectively killing off any form of hope for the Nigerians.
Elsewhere in Kigali, Tunisia were simply too much for Niger who finished the game with a man-less after Oumarou Balley was sent off on 74 minutes for a second yellow card. The 2011 champions led 2-0 at half time thanks to a Saad Bguir brace.
Ahmed Akaichi increased the tally on 79 minutes before Mohamed Ben Amor took the game beyond ‘Les Menas’ two minutes later. Hichem Essifi completed the goal harvest with the fifth on the stroke of full time.
Guinea – Nigeria: Ibrahima Sory Sankhon (Guinea)
Niger – Tunisia: Ahmed Akaichi (Tunisia)
Match statistics: Guinea – Nigeria
Match statistics: Niger – Tunisia