Nigeria cruised through seven-time champion Egypt thanks to Kelechi Iheanacho’s brace.
In the 30th minute, he scored with a spectacular half-volley on the turn.
Egypt goalkeeper Mohamed El Shenawy tipped a Taiwo Awoniyi header over the bar and twice denied Chidera Ejuke.
After losing in Garoua, the Pharaohs were silent.
Having Victor Osimhen, Emmanuel Dennis, and Odion Ighalo all ruled out of the Super Eagles squad for Cameroon, Iheanacho’s performance upfront would be welcomed.
During the first half, he fed Awoniyi, who had a tame effort saved shortly before the break.
Nigeria, the three-time African champions, pushed for a second goal after the break, but El Shenawy denied substitute Chidera Ejuke twice.
With new boss Jose Peseiro only able to watch from the stands, the West Africans needed only one goal to win.
Four weeks before the competition, the Super Eagles fired long-time coach Gernot Rohr after a poor World Cup qualification campaign.
Egypt was poor for much of the match, managing only one shot in the first 70 minutes.
Nigeria’s tempo isolated Liverpool’s Mohamed Salah upfront.
With 20 minutes left, Ahmed Sayed found the forward, but his mishit attempt was saved by Maduka Okoye’s legs.
Holders Algeria Held
Algeria opened their Afcon defense with a goalless draw against a tenacious Sierra Leone team in Group E.
Alhaji Kamara missed two chances for the Leone Stars in the first half.
Algerian attacker Yacine Brahimi hit the post after the break, while Riyad Mahrez’s low attempt was saved by keeper Mohamed Nbalie Kamara.
At the end of regulation, Nbalie Kamara denied Ramy Bensebaini.
Former England defender Steven Caulker produced two key blocks to help Sierra Leone keep a clean sheet in their first Nations Cup appearance since 1996.
Algeria extended their unbeaten run to 35 senior internationals, closing in on Italy’s global record of 37 matches unbeaten, but coach Djamel Belmadi will be disappointed his troops couldn’t beat a 108th-ranked team.
The Desert Foxes created numerous chances in the second half but failed to capitalize on them, with substitute Said Benrahma missing a five-minute chance.
A free header from a corner was right at Nbalie Kamara, who went to his knees in ecstasy at the end of the game.
In Douala’s Japoma Stadium, the Sierra Leone goalkeeper had ridden his luck on occasion, usually coming to the edge of his area to take away danger.
Nbalie Kamara made a successful sliding block tackle on Islam Slimani in the first half and stopped a shot from Manchester City winger Mahrez midway through the second half.
Early on, after Slimani had hit the side-netting from a tight angle for the North Africans, striker Kamara almost gave Sierra Leone the lead.
The Algerian goalkeeper Rais M’Bolhi saved a 25-yard free-kick from Mohamed Buya Turay.
Just after the restart, Kamara had a goal disallowed for offside before Algeria took complete control.
Former Tottenham defender Caulker diverted a Sofiane Bendebka effort away for a corner and then charged down another from the attacker.
Sierra Leone’s last-gasp goal secured a point, giving the West Africans hope of making the last 16.
On Sunday, Algeria plays Equatorial Guinea and Sierra Leone plays Ivory Coast.
Guinea-Bissau missed a late penalty as they were held by Sudan
Guinea-Bissau missed a late penalty as Sudan held them in their Group D opening.
Pele’s 82nd-minute penalty was saved by Sudan goalkeeper Ali Abou Achrine, with Piqueti grabbing the rebound.
Mr. Abou Achrine was ruled to have fouled Steve Ambri.
In the first half, Joseph Mendes hit the post with a header, and Frederic Mendy’s late effort was cleared.
Guinea-Bissau has now gone five games without scoring in the Nations Cup and has an uphill task to reach the knockout stage for the first time.
Sudan, making their first appearance in the tournament in ten years, was happy with a point at half-time, with interim coach Burhan Tia overseeing the 1970 winners for the first time.
A dismal showing in the Arab Cup saw the Birds dismiss former coach Hubert Velud last month.
Sudan’s Mohamed Abdelrahman came close to scoring, prompting a save from Guinea-Bissau goalkeeper Maurice Gomis.