Newcastle’s Fabian Schar formed part of two changes from their defeat at Palace as Leicester’ sole change resulted in the return of Harry Maguire.
After a tentative opening, Newcastle went close on 15 minutes in with Solomon Rondon’s free-kick flying narrowly over the top.
Leicester draw a response six minutes later, as James Maddison combined with Ben Chilwell for a low strike which Martin Dubravka saved easily.
The Magpies drew first blood 32 minutes in after Ayoze Perez headed a well-orchestrated delivery from Matt Ritchie into the far post.
The lack of clear-cut openings continued with the commencement of the second half, with Jamie Vardy failing to turn home Chilwell’s delivery by a whisker on the hour mark.
Leicester coach Brendan Rodgers made a double change on 72 minutes, with Kelechi Iheanacho and Nampalys Mendy coming on for Demarai Gray and Wilfred Ndidi.
Right after the midway point, Perez failed to take a first-time shot 76 minutes in after squeezing into the area, leaving Kasper Schmeichel to collect comfortably.
The Tigers threatened an equaliser on 79 minutes after Youri Tielemans played in Vardy, who failed to capitalise with a horrid first-time shot that flew over the top.
As the dust settled, the Magpies sealed a massive victory to go to 13th place from ninth whilst the hosts suffer their first home defeat under Brendan Rodgers to remain in seventh.