With an immediate return to the Championship almost inevitable, Leicester had enormous pressure on them to try and finally give their fans something to cheer for, but any hope was almost immediately extinguished as Newcastle opened the scoring inside two minutes.
A brilliant team move saw Joelinton feed Harvery Barnes on the left flank, and the former Foxes winger released the overlapping Tino Livramento, who picked out Jacob Murphy at the back post to prod home.
One very quickly became two on 11 minutes after Fabian Schar rocked the crossbar with a thunderous effort from inside his own half, and Murphy was on hand to tuck in the rebound.
Leicester, clearly shellshocked after going two down inside the opening quarter-hour, struggled to lay a glove on the Magpies, who threatened throughout the first half.
And Eddie Howe’s men added a third goal on 34 minutes when a quick counter up the pitch culminated with Mads Hermansen parrying Joelinton’s shot into the path of Barnes, who instinctively tapped into an empty net.
Having conceded 21 goals since they last scored - and lost their previous seven home league games without finding the net - even a consolation would’ve been a welcome relief for the home fans.
There’d be no such joy, with Newcastle even threatening to pull further ahead when EFL Cup final hero Dan Burn failed to steer his header on target from a corner.
Three goals to the good, Howe took the opportunity to rest key players, withdrawing Brazilian duo Joelinton and Bruno Guimarães, along with Alexander Isak just after the hour mark.
On an otherwise miserable night for Leicester, the only bright moment came when Ruud van Nistelrooy handed 15-year-old Jeremy Monga his professional debut - the second-youngest debutant in PL history.
The Magpies coasted through the final quarter hour with no trouble on Nick Pope’s goal, extending their unbeaten H2H run to six games (W5, D1) while keeping Leicester 15 points adrift of safety.
Flashscore Man of the Match: Jacob Murphy (Newcastle United)