Skipper Jamaal Lascelles was the hero at both ends of the park as Newcastle recorded their first Premier League win on the road.
The central defender netted the only goal of the game, a powerful header, to ensure United, in the absence of Rafa Benitez, took all three points back North.
But, perhaps just as telling, was his goal-line clearance that kept the game goalless just after the break.
Benitez may well have been at home but he was masterminding things from his sofa, making two changes to the side that won last time out against West Ham United.
In came Jacob Murphy for Christian Atsu and Jesus Gamez for the injured Chancel Mbemba.
On the bench DeAndre Yedlin returned after a long lay-off, with Florian Lejeune and Jonjo Shelvey also in the matchday 18.
As a spectacle the opening 25 minutes was a one for the purists - and that's being kind.
Both sides had just a weak Isaac Hayden shot to show for their efforts.
But around the half hour mark this slow burner really caught fire.
A Matt Ritchie long ball found Murphy, after an error by Federico Fernandez, but his lob was wayward, shooting high into the travelling Geordies behind the goal.
Joselu, having gone close with an earlier volley looked to have put United ahead 10 minutes before the break when his flicked header from a Ritchie centre was saved quite magnificently by Lukas Fabianski.
Every time Mikel Merino steps out on to the park, whether that be in United colours or for Spain Under-21s, he looks a class act. Today was no different.
But he was the cause of controversy when he took a very suspect tumble on the edge of the Swans area. He wanted a penalty, ref Mike Jones was having none of it. It'll be interesting to see whether the FA take a look, having adjusted the laws on retrospective bans for diving.
While United dominated in terms of possession, it was the hosts who probably had the best chance of the half - Alfie Mawson somehow heading wide from seven yards when it looked easier to score.
Overall, United could be pleased with their opening 45.
Paul Clement's men came out with renewed purpose after the break, though.
And they should have been in front when a delightful Leroy Fer ball set former NUFC target Tammy Abraham free. And it looked fated the striker would net when he rounded Rob Elliot, but Lascelles was on hand to save the day, sliding in to clear off the line. It was a let off for United.
But, as had happened in the opening 45, after a bright start Swansea began to fade and Perez had the chance to edge United in front on 73, bursting clear after a neat one-two with Javier Manquillo but his effort was saved by the feet of Fabianski.
United were in front, though, soon after as a curling corner from the left was met by the rising Lascelles, who beat Mawson to nod home the winner.
And despite the Swans throwing the kitchen sink at United in the closing stages Elliot between the sticks and United as a whole held firm to make it two wins on the bounce.