The African champion was humbled on Friday, with Cameroon losing 4-0 in Nigeria to see its World Cup hopes slipping away.
Cameroon wasn't the only big team left struggling in World Cup qualifying. Ghana was held 1-1 at home by Republic of Congo and needed a late equalizer for a point. Ghana still hasn't won in qualifying. South Africa led early but still lost 2-1 in Cape Verde.
A roundup of Friday's five games:
Tunisia won the biggest battle of Group A so far, beating Congo 2-1 to take top spot outright. Only the five group winners in Africa will qualify for the World Cup and, with three games to come, Tunisia is in position to return after missing the last two tournaments in South Africa and Brazil. Yassine Meriah scored for Tunisia with an early penalty. Ghilane Chaalani netted the winner two minutes after halftime, and after Cedric Bakambu had equalized two minutes before halftime.
After its African Cup of Nations triumph in February, Cameroon had high hopes of taking that form into World Cup qualifying and closing the gap on group leader Nigeria. Those hopes were convincingly dashed as Nigeria strengthened its hold on the outright qualifying place. Nigeria scored twice in each half, through Odion Ighalo, captain Jon Obi Mikel, Victor Moses and Kelechi Iheanacho.
Ighalo celebrated by revealing a T-shirt under his team uniform with a message of support for Nigeria goalkeeper Carl Ikeme, who has leukemia. He was shown a yellow card.
Nearly everything went wrong for Cameroon, including when halftime substitute Eric Choupo-Moting had to go off injured 15 minutes after coming on. Seven points behind Nigeria halfway through the qualifiers, it's going to be tough for Cameroon to close that gap and it must now beat Nigeria at home in Yaounde on Monday or the African champion will definitely be sitting out the World Cup in Russia next summer.
Morocco provided the most consummate performance of the day, crushing Mali, which had two men sent off, 6-0. Hakim Ziyech scored twice. Bakaye Dibassy and Mohamed Konate were sent off for Mali, and the Malians played the last 23 minutes with nine men. They conceded three goals in that period.
Morocco goes top ahead of Ivory Coast's game in Gabon on Saturday.
South Africa was 1-0 up against group struggler Cape Verde with a 14-minute goal from Tokelo Rantie.
Nuno Rocha replied twice in the space of five minutes, the second from the penalty spot, to give Cape Verde its first point of the qualifiers.
Group leader Burkina Faso is away at Senegal on Saturday with just one point now between the top and bottom teams.
Ghana's lethargic qualifying campaign continued. A World Cup quarterfinalist two tournaments ago, Ghana had to fight for a home draw against Republic of Congo, with Atletico Madrid midfielder Thomas Partey's goal five minutes from time giving it a point.
Winless in three games in qualifying, and five points behind group leader Uganda, Ghana looks set to miss out on Russia 2018.
Associated Press writers Francis Kokutse in Accra, Ghana, and Andrew Jackson Oryada in Kampala, Uganda, contributed to this report.
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