Despite being the underdogs at King Power Stadium, goals from Michail Antonio, Pablo Fornals and Jarrod Bowen secured all three points and a bad day at the office for Brendan Rodgers.
With neither side able to gain a foothold in the early stages, Antonio’s opener was the first effort on target.
Aaron Creswell’s cross drifted over a line of Foxes defenders, and Antonio peeled off at the back post to head past Kasper Schmeichel.
But if Leicester’s defence were caught short for West Ham’s first goal, they were completely AWOL for the second.
Creswell’s clearance caught them too high up the pitch, and Fornals raced on and on and fired past Schmeichel.
With the Foxes unable to drag themselves into it after the break, the Hammers pushed for a third, as Declan Rice rattled the crossbar.
The visitors did finally secure three goals and three points in the closing stages, as Bowen slotted home Fornals through ball.
FULL TIME AT THE KING POWER STADIUM IT’S LEICESTER CITY 0 WEST HAM 3