The Foxes shifted formation to the four-man defence that saw them dominate Brighton & Hove Albion in their last match, but to no effect as Everton controlled the game and took the points back to Merseyside.
Richarlison's curling effort squeezed under the arms of the unsighted Kasper Schmeichel to put the away side in the lead, before Mason Holgate's first Premier League goal in the aftermath of a scramble in the box killed off the game with 72 minutes played.
Leicester's night would worsen as penalty decision overturned by VAR and a disallowed Ayoze Perez goal consolidated a miserable outing.
Leicester's lack of attacking urgency
The East Midlands side were sharp on the ball, quick to turn defence in attack and relentless in trying to create opportunities against Brighton. Fast forward a couple of days and Leicester could not have played anymore different to that display.
The Foxes were sloppy in possession, slow to play forward and lacking in creativity as they played in front of an Everton defence who looked comfortable all game.
Despite Everton regaining shape incredibly quickly to halt any counter attacks that Leicester may trigger, the home side gave them every opportunity to do so. Only on a handful of occassions did the Foxes move the ball quickly and cut through the Everton defence, but as it was throughout the match, the final ball was lacking.
Leicester started the game well and looked to strike early, but lost all momentum when Richarlison notched the opener. They never quite recovered from that moment, despite a Jamie Vardy header straight into the keeper's arms in the first half, and only looked threatening in attack at the end of the match when the points were already out of their grasp.
Defensive display costs Foxes
It wasn't just the attacking urgency that was lacking, but the defensive display also left little to be desired.
James Justin allowed Richarlison to cut inside on his right foot for the first goal, but it was the second goal especially which emphasised the poor defensive display.
Set pieces have proved an issue for Leicester all season and that trend continued with Holgate's goal. Schmeichel denied the initial header from Everton corner, before producing a world-class second save to deny Dominic Calvert-Lewin. Holgate notched with the third rebound as the Leicester defence stood by and watched the events unfold.
The Foxes will be boosted by the return of Jonny Evans and Timothy Castagne from suspension and injury respectively, but will have to improve drastically as they face a Tottenham Hotspur side who boast the likes of Son Heung-min and the scourge of Leicester, Harry Kane.
Everton frustrate Foxes
If the Toffee's game against Chelsea was anything to go by for Leicester, letting them score the first goal would be costly and it ended up being so.
After Richarlison scored, the emphasis was on Leicester to get back into the game and that played into Everton's hands as they could sit back and starve the home side of any creativity. They stayed compact, defended resolutely and dealt with anything that Leicester threw at them.
They would then break up play with tactical fouls as well as winning freekicks high up the pitch to halt any momentum that Leicester may have gathered.
All of this meant that the Toffees reduced the Foxes to only two shots on target all game, emphasising how effective their game plan was.