Hosts Ghana left it late to beat their close rivals Nigeria despite having a man sent off whilst the Ivory Coast had less trouble in seeing off Guinea.
Nottingham Forest striker Junior Agogo was the hero as the host nation beat traditional rivals Nigeria 2-1 in Accra to reach the semi finals despite the sending off of centre-back John Mensah.
Nigeria took the lead after 34 minutes when Aiyegbeni Yakubu coolly converted a penalty awarded after Anthony Annan brought down Ikechukwu Uche. The goal was against the run of play but Nigeria were playing with renewed confidence following their 'miracle' qualification after beating Benin and Mali's defeat to the Ivory Coast.
Ghana's equalizer came in first half injury time when talismanic midfielder Michael Essien rose to head Quincy Owusu-Abeyie's left-wing cross home. The header thumped against Nigeria's post before trickling agonizingly across the line before nestling just inside the opposite upright.
The goal left a pulsating atmosphere in the stadium throughout half-time and Ghana emerged for the second half full of confidence that they could grab a winning goal. That eagreness, however, left holes at the back and when Nigerian winger Peter Odemwingie was played clean through defender John Mensah could only bring him down and face a red card for denying a goalscoring opportunity.
Despite going a man down, Ghana still created chances and the winning goal came when Sulley Ali Muntari's low cross found an unmarked Agogo at the back post who drove the ball into the roof of Nigeria's net.
The Super Eagles had to take risks in search of an equalizer and Ghana might have increased their lead when Laryea Kingston shot wide but they hung on for a win that left the streets of Accra in raucous mood.
The Ivory Coast had less difficulty in beating a poor Guinea side desperately missing suspended playmaker Pascal Feindouno. In a poor first half the Elephants rarely threatened but took the lead in the 25th minute with a peculiar goal from right-winger Abdul Kader Keïta whose low cross-shot from a tight angle caught Guinea goalkeeper Kemoko Camara out of position, squeezing between him and his near post.
The game was tight and cagey until the last twenty minutes, when the Ivory Coast brushed aside Guinea with four goals in an extraordinary quarter of an hour period. Didier Drogba powered onto Arthur Boka's pass to sidefoot past Camara before playing in Chelsea team-mate Kalou two minutes later, who rounded the goalkeeper to walk the ball into an unguarded net.
Kalou added another from close range with ten minutes remaining after a surging run from Yaya Touré and substitute Bakari Koné, scorer of a magnificent goal against Holland in the 2006 World Cup, hammered home from long range in the 85th,
The emphatic result cements Ivory Coast's place as tournament favourites; they have now scored thirteen goals in four matches, conceding just once in the shape of a last minute consolation goal from Benin's Razak Omotoyossi.
Ghana now face the winner of tomorrow's Tunisia-Cameroon match while Ivory Coast will fancy their chances against either holders Egypt or the increasingly impressive Angolans.
Results
GHANA 2 (Essien 45', Agogo 83') NIGERIA 1 (Yakubu pen 35')
IVORY COAST 5 (Keïta 25', Drogba 70', Kalou 72', 81', B. Koné 85') GUINEA 0
