These are the pick of the eight third round, first leg fixtures from which the overall winners will advance to a mini-league tournament provisionally set for December and hosted by a qualifier.
The top three finishers secure places at the first Olympics hosted by London since 1948 and the fourth-placed team go into a play-off with an Asian country in the English capital next April.
Proud Olympic record
African nations have a proud football record during the past five Olympic Games, with Nigeria collecting gold and silver medals, Cameroon gold and Ghana bronze.
While Tanzania were stunning Cameroon two months ago, Nigeria flexed their muscles by hammering nine goals past Equatorial Guinea in a home-and-away tie, with Ekigho Ehiosun grabbing four to become leading scorer in the qualifiers.
"Many former African football minnows have made considerable progress and there is less of a divide in terms of quality. That is a reason why the match against Sudan will be far from easy," he warned.
South Africa drew 0-0 and won 1-0 in Mauritius last week as they prepared to face Benin in Cotonou and the return of leading scorer Bongani 'Drogba' Ndulula from champions Orlando Pirates should boost their fire power.
There is a strong north African presence and all have home advantage, with Algeria playing Zambia, Morocco meeting Congo DR and Tunisia facing Senegal.
Although qualifiers on all continents are restricted to U-23 players, the 15 qualifiers plus hosts Great Britain can field three over-age footballers during the tournament.