GAROUA, Cameroon — Nigeria’s 100% record in the group stage meant nothing as it was knocked out 1-0 by Tunisia in the last 16 of the African Cup of Nations on Sunday.

Youssef Msakni’s low, swerving shot just after halftime was the only goal, leaving Nigerian players slumped on the field in disappointment at the end.

Nigeria’s task was made even harder when Everton’s Alex Iwobi was shown a straight red card for raking his studs down the ankle of Msakni in the 66th minute. Iwobi was sent off seven minutes after he arrived as a substitute.

Nigeria had emerged as maybe the top contender for the title after it was the only team to win all its group games. Tunisia lost twice in the group stage and only went through as one of the best third-place teams but closed Nigeria down in a cagey game in Garoua on the first day of the knockout stage.

“We allowed them to get a foothold in the game,” said Nigeria’s Joe Aribo. “Can’t take anything away from them, but we should have been better.”

Tunisia got the job done without coach Mondher Kebaier, who was isolating in his hotel room instead of standing on the sidelines after a positive test for the coronavirus.

Tunisia will play Burkina Faso in the quarterfinals.

Burkina Faso beat Gabon in a penalty shootout in Limbe earlier Sunday and hours after mutinous soldiers seized control of a military base back home in Burkina Faso, raising fears of a coup attempt.

Substitute Ismahila Ouédraogo buried the decisive spot kick and Burkina Faso won the shootout 7-6 to finally prevail over a brave Gabonese effort.

Burkina Faso led 1-0, and Gabon had a man sent off in the 67th. But 10-man Gabon equalized in injury time through an own-goal by Burkina Faso midfielder Adama Guira to send the game to extra time.

It stayed 1-1 through extra time.

Burkina Faso twice had opportunities to win the shootout after Gabon players missed. But Burkina Faso players stepped up and also failed.

Ouédraogo’s winning penalty was the 18th of the shootout. He scored after Gabon’s Lloyd Palun hit the post for his team’s third and final miss.

Burkina Faso was 1-0 up in normal time through a first-half goal by captain Bertrand Traoré when Gabon had defender Sidney Obissa sent off with just over 20 minutes to go for a second yellow card.

Obissa had blatantly pulled a Burkina Faso attacker back by the shirt off the ball as the Burkinabes were surging forward.

It was a miserable day for Obissa, who picked up his first yellow card when he gave away an early penalty with a push on Burkina Faso’s Issa Kaboré on the edge of the area.

Traoré missed that penalty at the start of the game but made up for it 10 minutes later when he ran onto a through ball and slotted his shot underneath Gabon keeper Jean-Noël Amonome, who had come rushing out.

The ball clipped the inside of the post and went in, and Traoré leaped over the advertising boards and ran across an athletics track to celebrate right in front of a giant Burkina Faso flag in the crowd.

Chasing the game at 1-0 down, the 10 men of Gabon lived dangerously after Obissa took a walk but they raised themselves for one final effort from a corner in the first minute of injury time and a header by Gabon captain Bruno Ecuele Manga bounced off Guira and into his own net to take it to extra time.

Host Cameroon plays tournament debutant Comoros in the last 16 on Monday, when Comoros looks like it will be forced to field an outfield player as a goalkeeper because of a virus outbreak in its squad.

Guinea plays Gambia, another debutant, in the other game.