Magpies boss Steve Bruce again had to answer questions about when Almiron would break his duck in the build-up to the game, the Paraguayan having been on Tyneside for nearly a year without hitting the back of the net.
It looked like neither side would score on a frustrating afternoon in the north east until Almiron popped up with the winner seven minutes from time, the midfielder smashing the ball beyond Vicente Guaita after a knockdown from Andy Carroll.
Palace had created the better chances before Almiron’s winner, Christian Benteke and Wilfried Zaha passing up the best of the opportunities as Roy Hodgson was defeated for the first time in a Premier League game by a Bruce-led side.
Newcastle began brightly and should have been ahead after six minutes when Isaac Hayden was played through on goal, rounded the Palace goalkeeper Guaita but then slipped at the crucial moment and the chance went begging.
The Eagles grew into the half and created the better of what chances there were, Benteke and Cheikhou Kouyate heading over when they should have done better.
Zaha then forced Martin Dubravka into a smart save at his near post after the best move of the half from Palace came to nothing.
James McArthur nearly gave the Londoners the lead when he was played through on goal but was denied by Dubravka from point-blank range.
Benteke, still chasing his first goal of the game, then passed up a great chance when shooting straight at Dubravka as Hodgson’s men grew increasingly frustrated.
The decisive moment then arrived in the 83rd minute and Newcastle were able to dig in for the three points after taking the lead, lifting them up to ninth, while Palace, without a win in three, have slipped out of the top 10.