Star-packed Algeria came to the Africa Cup of Nations in Gabon as one of the title favourites, but they need a miracle in Franceville Monday to reach the quarter-finals.
A team including African Footballer of the Year Riyad Mahrez must defeat Group B winners Senegal, and hope fellow strugglers Zimbabwe beat Tunisia in Libreville in a simultaneous kick-off.
Those results would see Algeria and Zimbabwe sharing second place with four points each, leaving goal difference, goals scored or the drawing of lots to separate the sides.
Judged by the four matches so far in Franceville, however, victories for Algeria and Zimbabwe are unlikely as Senegal and Tunisia have been much more impressive.
Senegal are assured of finishing first and staying in the southeastern Gabonese city for a quarter-final against the Group A runners-up.
Tunisia need only draw with Zimbabwe to seal second spot and secure a Libreville date with the Group A winners.
Belgium-born Algeria coach Georges Leekens accepts the former champions are facing a mammoth task.
“Senegal play good football and, in an ideal world, we would have qualified before facing them,” he admitted.
“To be frank, this is going to be a very tough match for us to win. We dare not give away soft goals like we did against Tunisia.
“Unfortunately, we no longer have our destiny in our own hands,” added the handler who took Tunisia to the 2015 Cup of Nations quarter-finals before quitting over a bonus dispute.
An own-goal by captain Aissa Mandi and a suicidal back-header by fellow defender Faouzi Ghoulam led to the 2-1 defeat by neighbours Tunisia.
Senegal coach Aliou Cisse says he will not rest his first-choices, even though the result is of academic interest to him with first place sewn up.
“We intend fielding our strongest side,” he said. “This fixture has the potential to be a thriller and all the players want to compete.
“I believe that football followers the length and breadth of Africa are looking forward to this match.”
A glance at the line-ups makes it clear why the final-round group game is so eagerly anticipated.
The Senegal attack includes Liverpool star Sadio Mane, third in the 2016 African Footballer of the Year poll, and Keita Balde of Lazio.
Henri Saivet, a Newcastle United midfielder on loan to Saint-Etienne, is another Teranga Lion in form, creating the first goal in the 2-0 win over Zimbabwe and scoring the second.
Among the reasons Algeria were rated potential champions by pundits was the presence of winger Mahrez.
But after being a pivotal figure in the sensational 2015-2016 English Premier League title success of Leicester City, his form with club and country has dipped.
Mahrez did score twice against Zimbabwe in a 2-2 draw, but was largely anonymous for long periods, and then well contained by Tunisia.
Leicester team-mate Islam Slimani and former BBC African Footballer of the Year Yacine Brahimi are some of the other stars in the Algerian line-up who need to raise their games significantly.
Wahbi Khazri, seldom used by Premier League strugglers Sunderland this season, came off the bench to trouble Senegal during a 2-0 defeat and was instrumental in the victory over Algeria.
Fellow attacker Naim Sliti boasts that Tunisia play “beautiful football”, but all Polish coach Henryk Kasperczak wants against Zimbabwe is one point.
A concern for the Tunisians is the fitness of experienced goalkeeper Aymen Mathlouthi, who was forced to retire injured during the win over Algeria.
After a gutsy show against Algeria, Zimbabwe were overwhelmed by Senegal and fortunate to finish with just a two-goal beating.