Match ends, Nigeria 1, Burundi 0.
Three-time winners and 2013 champions Nigeria edged past tournament debutants Burundi at the Africa Cup of Nations.
Second half substitute Odion Ighalo scored the only goal after 77 minutes in Alexandria with a curled finish past Burundi goalkeeper Jonathan Nahimana.
Burundi - the lowest-ranked side at the tournament - had struck the crossbar in the first half through defender Frederic Nsabiyumva's looping header.
Guinea face Madagascar in the other Group B match later on Saturday.
FC Midtjylland striker Paul Onuachu had Nigeria's first real chance on goal after 12 minutes as his header forced Burundi goalkeeper Jonathan Nahimana in to action.
Burundi, 134th in the world standings, remained unfazed and Cedric Amissi's close-range shot required a good save from Nigeria's Daniel Akpeyi.
Arsenal's Alex Iwobi and Villarreal 20-year-old Samuel Chukwueze offered the Super Eagles' main attacking threat, but Gernot Rohr's side were frustrated by a resolute and organised Burundi side - captained by Stoke City striker Saido Berahino - until Ighalo's introduction.
The Shanghai Greenland Shenhua striker, formerly of Watford, produced a quality finish just four minutes after entering the field, following Ola Aina's delightful back-heeled pass.
Nigeria were without striker Samuel Kalu, who had been taken to hospital after suffering from "severe dehydration" in training on Friday - a day after players' union Fifpro had called for the tournament organisers to increase their planned number of heat breaks from two to four per match.
The Super Eagles now face Guinea on Wednesday (15:30 BST), while Burundi take on fellow debutants Madagascar on Thursday (15:30).
Analysis
By BBC Africa's Robert Misigaro:
For a first outing at a major tournament, Burundi can hold their head high as they showed an experienced Nigerian side they were ready for a showdown.
Burundi's inexperience at this level of the game did not show in terms of discipline, approach to the game and composure, apart from a clear lack of finishers.
Even though they lost, Burundi have a lot to be proud of and can hope to do better against a lesser opponent. A 1-0 score against Nigeria in their first ever Africa Cup of Nations game is nothing to be ashamed of.
Meanwhile, Nigeria can expect anything but an easy ride in this tournament.
Line-ups
Nigeria
Formation 4-2-3-1
- 16Akpeyi
- 12ShehuSubstituted forAwaziemat 42'minutes
- 5Troost-Ekong
- 22Omeruo
- 2Aina
- 4Ndidi
- 8Etebo
- 13Chukwueze
- 10MikelSubstituted forMusaat 58'minutes
- 18Iwobi
- 14OnuachuSubstituted forIghaloat 73'minutes
Substitutes
- 1Ezenwa
- 6Balogun
- 7Musa
- 9Ighalo
- 11Onyekuru
- 15Simon
- 19Ogu
- 20Awaziem
- 21Osimhen
- 23Uzoho
Burundi
Formation 4-4-2
- 1Nahimana
- 15Moussa
- 16Nshimirimana
- 19Nsabiyumva
- 8Duhayindavyi
- 20MoustaphaSubstituted forKamsobaat 59'minutes
- 5Bigirimana
- 10NahimanaBooked at 63minsSubstituted forNduwarugiraat 76'minutes
- 17Amissi
- 18BerahinoSubstituted forAmissiat 90+2'minutes
- 7Abdul Razak
Substitutes
- 2Sabumukama
- 3Kamsoba
- 4Kwizera
- 6Nizigiyimana
- 9Mavugo
- 12Shabani
- 13Ndikumana
- 14Ngandu
- 21Amissi
- 22Nduwarugira
- 23MacArthur
- Referee:
- Bernard Camille
- Attendance:
- 3,192
Match Stats
- Possession
- Home65%
- Away35%
- Shots
- Home15
- Away15
- Shots on Target
- Home3
- Away6
- Corners
- Home4
- Away6
- Fouls
- Home19
- Away22
Live Text
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Full Time
Second Half ends, Nigeria 1, Burundi 0.
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Corner, Burundi. Conceded by Kenneth Omeruo.
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Corner, Burundi. Conceded by Ola Aina.
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Foul by Odion Ighalo (Nigeria).
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Frederic Nsabiyumva (Burundi) wins a free kick in the defensive half.
Substitution
Substitution, Burundi. Mohamed Amissi replaces Saido Berahino.
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Offside, Burundi. Gael Bigirimana tries a through ball, but Cédric Amissi is caught offside.
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Attempt saved. Gaël Duhayindavyi (Burundi) left footed shot from outside the box is saved in the centre of the goal. Assisted by Gael Bigirimana.
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Hand ball by Ola Aina (Nigeria).
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Wilfred Ndidi (Nigeria) wins a free kick in the defensive half.
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Foul by Fiston Abdul Razak (Burundi).
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Attempt missed. Odion Ighalo (Nigeria) right footed shot from outside the box is too high. Assisted by Alex Iwobi.
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Chidozie Awaziem (Nigeria) wins a free kick in the defensive half.
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Foul by Frederic Nsabiyumva (Burundi).
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Attempt blocked. Christophe Nduwarugira (Burundi) left footed shot from the centre of the box is blocked. Assisted by Cédric Amissi.
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Corner, Burundi. Conceded by Chidozie Awaziem.
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Foul by Odion Ighalo (Nigeria).
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Frederic Nsabiyumva (Burundi) wins a free kick in the defensive half.
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Kenneth Omeruo (Nigeria) wins a free kick in the defensive half.