Derbies take centre stage on Tuesday as the second round of Group A games takes place in Africa's Olympic qualifiers.
Hosts Morocco face fellow north Africans Algeria, before Nigeria meet Senegal in an all-West African clash.
If the first game in Tangiers were to end in a draw, then defeat for either Nigeria or Senegal in their clash would send the loser home.
"We lost our first game so if we want qualification, we have to win against Nigeria," said Senegal's Kara Mbodj.
"We have a good team. I know the Nigerian side well, having played them three times, so I know it will be tough - but if we play fast, we will win the game."
Defeat for Nigeria could end their Olympic dreams, which would be a major blow for a team who won silver at the 2008 Olympics in Beijing.
Both Morocco and Algeria are in the driving seat after 1-0 wins over Nigeria and Senegal respectively in the opening round of matches.
The hosts needed a penalty to beat Nigeria in the opening game of a tournament that is doubling as Africa's inaugural Under-23 Championships.
"To make it easy, we will go for the three points against Algeria," Morocco coach Pim Verbeek told BBC Sport. "We want the three points to try to finish off our qualification."
"But Algeria are well-prepared and physically strong with intelligent players, so it will be a tough game."
Algeria have looked the most potent side in Group A, with Aberdeen's Mohamed Chalali proving a handful in the victory over Senegal - hitting the bar and missing several other good chances.
His blushes were saved by Mehdi Benaldjia's late goal but the match-winner is suspended for the Morocco clash after being sent off in injury time for an avoidable second booking.
Morocco have no injury worries ahead of the game but Verbeek admits their final pass needs to improve if they are to score goals.
It is a similar story for Nigeria who played some good passing football but rarely threatened the Moroccan goal in the first game with striker Stephen Worgu an isolated figure up front.
Nigeria will be without Kingsley Udoh who picked up an ankle injury after just two minutes against Morocco.
Senegal's squad has been boosted by the late arrival of Saliou Ciss and Serigne Kara Mbodj, the duo having just helped Tromso finish as runners-up in the Norwegian league.
Also available is Abdoulaye Ba, who plays in Portugal, after he was suspended for the opening game for two yellow cards in the qualifying rounds.
However Senegal will only have a squad of 19 players to chose from after France-based duo Zargo Toure (Boulogne-sur-Mer) and Pape Ndiaye Souare (Lille) were not released by their clubs.
The top three from this tournament automatically qualify for next year's Olympic Games in London while the fourth-placed side face a play-off against an Asian side for another spot at the Games.