Cameroon's four-year reign as holders of the African Nations Cup came to an end on Sunday while Nigeria established themselves as prime pretenders to the throne.
Nigeria beat the champions 2-1 in an absorbing duel between the continent's two footballing superpowers to book an intriguing semi-final against hosts Tunisia at Rades on Wednesday.
Cameroon had been seeking an unprecedented third successive Nations Cup title and a record fifth triumph.
Morocco also advanced to the final four on Sunday, dramatically coming back from the brink of defeat to beat neighbours Algeria 3-1 after extra-time in Sfax.
Marouane Chammakh scored a injury-time equaliser just as Algeria looked poised to continue their fairytale run in the tournament, to force the game into extra-time.
Then Youssef Hadji and Jawad Zairi added two more goals for Morocco, who meet Mali in Sousse in Wednesday's semi-finals.
Nigeria, who had never lost in nine previous Nations Cup quarter-final appearances, had to come from a goal behind to secure the win.
They equalised just before half-time when captain Jay Jay Okocha fired one of his trademark free kicks and John Utaka scored the winner on the breakaway in the 73rd minute.
Cameroon's striker Samuel Eto'o, who had displayed little of his potential in their three first-round matches, caught Nigeria with a quick counter punch for the first goal just as the Super Eagles looked to be taking charge of the game.
A long pass over the top of the
PERFECT PASS
Nigeria's winner was set up after Arsenal's Nwankwo Kanu played the perfect pass into the path of Utaka, whose finish mirrored that of Eto'o earlier effort.
The victory came despite a potentially disastrous start to the tournament for Nigeria, who lost their opening match and then kicked out three players from their camp for indiscipline.
"We showed everybody the character that is in the team, that no matter we're still a team and that we still have our ambition coming to Tunisia," said captain Okocha.
"We'll give our best to try and achieve our goal. We are sticking with one another."
Algeria were on the brink of continuing their run at the tournament before Morocco staged their comeback in a stadium overflowing with Algerians fans, who had several skirmishes with local police before and during the game.
French-born striker Abdelmalek Cherrad put Algeria 1-0 ahead with just six minutes left but poor marking allowed Chammakh to equalise seconds from the end of stoppage time.
Algeria, whose coach Rabah Saadane had described their progress past the first round as a "miracle", then faded away in extra time as first Hadji and then Zairi turned the result around for the Moroccans.
Morocco are through to the semi-final for the first time since they hosted the tournament in 1988.