Nigeria avenged a humiliating Africa Cup of Nations qualifying loss to Guinea-Bissau three days ago by winning the rematch on Monday, while Algeria edged Niger to book a finals place.
Moses Simon was the Nigerian scorer in a 1-0 victory in Bissau, converting a 30th-minute penalty after Fali Cande fouled Bright Osayi-Samuel.
Simon fired the spot-kick into the right corner of the net as goalkeeper Jonas Mendes dived in the opposite direction.
Desperate for revenge after a solitary-goal loss to much lower-ranked Guinea-Bissau in Abuja last Friday, Nigeria looked likely winners for most of the top-of-the-table Group A clash.
Prolific Napoli scorer Victor Osimhen turned smartly in the penalty area as the hour mark approached only to see his low shot rebound off the far post.
Portuguese coach Jose Peseiro made five changes after the Abuja debacle with Nice forward Terem Moffi among those promoted.
But the scorer of 15 Ligue 1 goals this season did not impress and was replaced midway through the second half.
Victory returned Nigeria to first place with nine points after four rounds, followed by Guinea-Bissau (seven), Sierra Leone (five) and Sao Tome e Principe (one). Read more