Leicester strolled past MK Dons to reach the Carabao Cup quarter-finals in their first game after the World Cup.
Youri Tielemans and Ayoze Perez gave the Foxes a two-goal cushion by the break before Jamie Vardy added another.
Chances were sporadic for the hosts at Stadium MK and they did not make the most of their few opportunities.
Premier League Leicester were a step above and their sharpness in the final third was too much for the League One side to handle.
Thirty-eight days after the Foxes last played a competitive fixture, Brendan Rodgers' side did not look like a team who were lacking match-sharpness, and fired off early warning shots through Perez and Timothy Castagne.