First-time qualifiers Madagascar and outsiders Niger reached the African Nations Championship (Chan) semifinals for the first time on Saturday with convincing victories in Algeria.
Madagascar defeated Mozambique 3-1 in Constantine before Niger shocked two-time runners-up Ghana 2-0 in Oran to complete the last-four line-up.
Hosts and title favourites Algeria face Niger in Oran on Tuesday afternoon and Senegal play Madagascar in Algiers three hours later.
When the biennial tournament confined to footballers playing in their country of birth kicked off on January 13, no pundit mentioned Madagascar or Niger as potential semifinalists.
But Madagascar shocked Ghana and hammered Sudan to win Group C before proving too creative for sluggish Mozambique in the quarterfinals.
Niger did not impress in a dour draw with Congo Brazzaville, but they then upset Cameroon to top Group D before scoring early in each half to see off Ghana.
Algeria and Senegal will be favoured to contest the February 4 final at an Algiers stadium named after South African political icon Nelson Mandela, but they dare not underestimate their rivals.
Niger had history on their side against Ghana, having won the one previous Chan match between them, and a strong start led to an 11th-minute lead.
Imarana Seyni soared to connect with a cross into the six-yard box and his header was deflected past goalkeeper Ibrahim Danlad by Konadu Yiadom.
Niger went two goals ahead just four minutes into the second half with one of the best goals so far in the seventh edition of a tournament first staged 14 years ago in the Ivory Coast.
Ghana carelessly surrendered possession and a pass found Boubacar Hainikoye, who cut inside and sent a looping shot from the edge of the box over Danlad into the far corner of the net.
Substitute Kwame Otu had a Ghana goal ruled offside and squandered an added-time chance to score and set up a tense finish.
In Constantine, Madagascar pressed from the kick-off and led on 18 minutes when Solomampionona Razafindranaivo gave goalkeeper Victor Guambe no chance with a shot into the far corner.
The Malagasys had a second-half goal disallowed due to a foul in the build-up, but did not take long to confirm their superiority as Jean-Yves Razafindrakoto scored after a defensive mix-up.
A surging run and fierce shot by Marcio Ravelomanantsoa put the Indian Ocean nation three goals ahead before a late tap-in by Mozambique captain Isac de Carvalho reduced the deficit.