The opening batsman struck a majestic 110, as he and Samuel Mba 62 put on 148 for the first wicket, and pull his side clear in the final. That alliance was enough to put Nigeria out of sight, as Sierra Leone were overwhelmed by the opening stand, which lasted 34.1 overs.
Beyond that opening partnership, only Segun Ogundipe made a meaningful contribution, as Nigeria's total petered out to 242/9, assisted by 21 extras.
In response, Sierra Leone served up their worst batting performance of the tournament. They were bundled out for just 105, with skipper George Ngegba fighting a lone battle with 31.
Not for the first time, Peter Aho was the surgeon for Nigeria, with another five-wicket haul, which cut the chase in the bud. The damage inflicted on the middle-order was terminal, and Nigeria ran out 137-run winners.
Aho took the final wicket, fittingly, to spark wild celebrations from the strongest team in the competition. For their part, Sierra Leone could console themselves with a place in the first division, and a chance to go again for a place in the 2020 tournament proper.
In the battle for the last qualifying spot in Division 1, Tanzania got the better of Mozambique, posting a testing 215 all out. At 89/5, they had to depend on their middle-order to make the play, and 15-year old Dhrumit Mehta and Kartik Sayal stepped up.
Mehta weighed in with 37, while Sayal's 45 was vital in holding the whole thing together. Their 79-run alliance gave their bowlers something to work with, and that was all they needed.
Vieira Tembo struck a belligerent 90 for Mozambique, but his was a lone hand, as his mates fell all around him. Mozambique, plucky throughout the tournament, only scored 140, with Tembo the penultimate wicket to fall.
Tanzania had greater discipline with the ball, which was the difference. Mozambique gave away 36 extras, while Tanzania were miserly with nine, in just over 40 overs of endeavour. Mehta completed a fine day's work by snaffling 3/38, to add to his crucial contribution with bat.