Leicester City are through to the fifth round of the FA Cup courtesy of a couple of extra-time wonder strikes from Wilfred N'Didi and Damarai Gray.
Leicester took the lead immediately following the half-time interval, Demarai Gray weaving in from the left wing to find Marc Albrighton at the back post with a deep cross, before the former Aston Villa man headed the ball central for club stalwart Andy King to tuck home.
Derby replied on the hour mark, Abdoul Camara's freekick deflecting off youngster Ben Chilwell to wrong-foot goalkeeper Jonathan Mitchell and roll into an empty bottom corner.