The Ghana midfielder who had been away on international duty at the Africa Cup of Nations was thrown on by manager Rafa Benitez at the beginning of the second period in place of goal scorer Aleksandar Mitrovic.
Mitrovic was hurled off by Benitez to prevent him being sent off after a rash challenge on Ikeme in the first half went without punishment as he had been booked previously.
The win took the Geordies back to the top of the table after Brighton and Hove Albion had moved top earlier in the day following their 4-1 victory at home against Burton Albion.
Just one point separates both teams as the race to return to the Premier League continues in earnest. Newcastle cannot afford to slip up when they visit Norwich City on Tuesday night while Brighton welcome Ipswich Town.
Atsu would hope to find a starting spot in Benitez’s side after the distractions of the Afcon where the Black Stars finished in fourth place as they extended their 35-year-long wait for a senior title.