Naby Keita failed to spark Guinea's Africa Cup of Nations campaign into life as Kenneth Omeruo's goal sent Nigeria into the last 16.
Nigeria became the first team to qualify for the Africa Cup of Nations knockout phase as Kenneth Omeruo's goal earned a 1-0 win over Guinea in Group B.
In a largely uneventful contest in Alexandria, Nigeria made the breakthrough when Omeruo headed in from Moses Simon's 73rd-minute corner.
Liverpool midfielder Naby Keita returned to fitness to make his first start for either club or country since May 1, but could not inspire Guinea, who are in real danger of an early exit.
Guinea goalkeeper Ibrahim Kone had been the star performer with two excellent saves from a pair of Alex Iwobi efforts, but his display proved fruitless as Omeruo's header ended Nigeria's four-match winless streak against the Syli Nationale.
After coming on as a substitute in Guinea's draw with Madagascar, Keita almost marked his first start in eight weeks with an assist early on, but Sory Kaba failed to take the midfielder's throughball into his path.
Francois Kamano sent a free-kick just wide as Guinea kept up the pressure, though Nigeria would have had the lead before half-time had Kone not got down to Iwobi's effort.
Kone came to Guinea's rescue once more just after the hour, doing well to prevent another Iwobi strike dipping in.
Keita's underwhelming return came to an end in the 71st minute when he was replaced by Lass Bangoura, and Guinea's resistance was broken moments later – Omeruo glancing a header into the far corner after connecting with Simon's delivery.
Guinea rallied late on, though Nigeria had little trouble in holding out for a win which guarantees their place in the last 16 with a game to spare.
Key Opta Facts
- Nigeria have won their last six games at the Africa Cup of Nations, their longest streak in their history, never conceding more than one goal in each of their six encounters.- Guinea are winless in their last seven games at the Africa Cup of Nations (D5 L2), their longest streak in their history.- Guinea have conceded at least one goal in each of their last 14 AFCON games.