The west African country, who have made six appearances at the Olympics and took the 1992 bronze medals in Barcelona, were not expected to have much trouble with opponents who struggled to make the second round. However, after scraping a solitary-goal success over Somalia, the Sudanese went to Accra two weeks ago and triumphed 1-0 via a stoppage time goal from Martin al-Khalees.
It was no more than the east Africans deserved in a competition restricted to U-23 footballers until the finals as they squandered several chances before a cross led to the lone goal. Ghana will not find the sauna-like weather nor the partisan crowd to their liking in Omdurman - a venue few visiting football teams leave celebrating a victory.
All is not lost for the talented Black Meteors, though, with the inevitable complacency in the squad disappearing after the stunning first leg scoreline, and Sudan will do well to make the last-16 phase. Cameroon and South Africa are other 'big name' countries in uncomfortable positions after failing to maximise home advantage against Tanzania and Libya respectively.
A Mark Pangwoh brace earned 2000 Sydney gold medalists Cameroon a 2-1 home victory over Tanzania, but the central Africans may rue conceding a late first-half goal and the failure of Parfait Essengue to convert a penalty. South Africa were sitting pretty midway through the second half at home to Libya with a four-goal advantage, but a bizarre own goal and a last-minute strike from Sami al-Ghulla transformed the landscape.
This tie will be staged in Bamako, capital of Mali and the new 'home' of Libyan football as conflict rages further north. The other southern Africa contenders enjoy home advantage, but most have their work cut out with Botswana, Malawi, Mozambique and Swaziland needing to cancel two-goal deficits and only the Swazis having scored on the road.
Angola are slightly better off having held Senegal goalless in Dakar while the Congo-Uganda tie could swing either way with the visitors to Brazzaville ahead thanks to a Karim Ndugwa goal. A Mohamed Chalili brace helped Algeria defeat Madagascar 3-0 and it is hard to see the islanders turning the tables in Antananarivo while the Democratic Republic of Congo look a safe bet having triumphed 2-1 in Burkina Faso.
However, the 'bankers' of the 14-fixture schedule must be Nigeria, runners-up to Argentina at the 2008 Beijing Games, who thumped Equatorial Guinea 5-0 at home and rendered the return leg largely meaningless. Zambia are already through to the third round after completing a 3-0 overall victory over Rwanda in Kigali last weekend while Benin received a bye when Gambia withdrew.