Indeed a win over Billy Davies' side would see United as good as up if they string together four more wins.
The manner of the win was so one-sided, with Scunthorpe an embarrassment in the first half as United attacked at will and Chris Hughton's side could easily have been six up at the break.
Time after time Joe Murphy stood in the way of a rout in a game that looked nothing more than a training exercise at times for Newcastle.
The Iron went into the game having conceded the most away goals in the Championship - 39 - and in their first visit to Tyneside for 36 years, they got off lightly as they saw that figure rise to 42.
Andy Carroll scored in each half and Peter Lovenkrands put away the other to take both strikers to 14 for the season.
Kevin Nolan also thought he had reached that total but had a header disallowed and Jonas Gutierrez had another chalked off also for a borderline offside decision.
Scunny - firmly anchored in a relegation spot - are incredibly one of only four teams to have beaten table-topping United this season when they were 2-1 home winners in October.
But any hopes they may have had of stopping United from increasing their run to 19 unbeaten home games this season, evaporated after only ten minutes.
Danny Guthrie's corner picked out Carroll who was allowed to rise unchallenged and plant a powerful header across Murphy.
From then on it was merely a matter of how many United would score. On a few recent occasions Newcastle have exceeded expectations with the size of their wins. This latest success was to the contrary - they scored less than expected.
Within 60 seconds of going in front, Nolan's header was ruled out and that was followed by Lovenkrands rattling the woodwork from a Jose Enrique cross.
The overworked Murphy brilliantly clawed out a Carroll 25-yarder before Newcastle doubled their tally after 22 minutes.
Wayne Routledge's throughball was to perfection for Lovenkrands and the Dane's finish was as clinical as ever.
The pressure continued and Murphy was again at his best to keep out Lovenkrands and Iron skipper Rob Jones cleared off the line to again deny Lovenkrands.
The second half was more of an anti-climax but United saved the best for last when Carroll took Guthrie's crossfield pass in his stride to neatly dink the ball over Murphy and pick up a yellow card for his celebrations.
It could have been a lot more and the end could not come soon enough for Scunny.