Libya stunned Nigeria’s U-23 Eagles 2-0 Wednesday in the first leg of a 2020 Tokyo Olympic Games second round qualifier.
Montenegro-based Zakaria Alharaish scored after six and 69 minutes in a match moved from Libya to Ben Guerdane in neighbouring Tunisia for security reasons.
Nigeria, who are former gold medallists, suffered a major blow just before half-time when goalkeeper Adamu Abubakar was sent off for handling outside the box.
The teams meet again on Monday in Asaba with Nigeria, the 1996 Atlanta Olympics champions, seeking to avoid a shock early exit.
Olympic qualifiers are restricted to under-23 footballers with three over-age players permitted at recent finals.
The Democratic Republic of Congo, a strong football nation but with a poor age-limit competitions record, built a 2-0 home lead over Morocco in Kinshasa thanks to Jackson Muleka.
The striker from the top Congolese club, TP Mazembe, put the home side ahead just before half-time and netted again midway through the second half.
DR Congo have never qualified for an Olympics football tournament while Morocco have achieved the feat seven times, most recently for the 2012 London Games.
Sudan were another country to build a 2-0 first-leg lead at home, against highly rated Kenya in Omdurman, with in-form Waleed Bakhet bagging a brace.
Bakhet has played a pivotal role in Al Hilal reaching the CAF Confederation Cup quarter-finals, scoring six goals.
He struck after 33 and 60 minutes, leaving Kenya needing to score at least twice in Nairobi when the teams meet again on Tuesday.
Guinea edged Senegal 2-1 in a showdown between western African neighbours with Morlaye Sylla snatching the winning goal three minutes into the second half in Conakry.
Jules Keita had converted a Guinean penalty after 34 minutes and Ibrahima Ndiaye equalised four minutes later with a potentially crucial away goal for the Senegalese.
Zambia look set to secure a place among the qualifiers for the third round during June after building a 1-0 lead away to Malawi in Blantyre.
Fashion Sakala scored after 77 minutes and Zambia need only draw the return match in Lusaka this Sunday to progress.
There were two 0-0 draws, between Burundi and Congo Brazzaville in Bujumbura and surprise qualifiers South Sudan and Tunisia in Juba.
Africa has been allocated three places for Tokyo and Cameroon, winners of the 2000 Sydney gold medals, are already through to the third round after Sierra Leone were disqualified.