Leicester have scored two stunning goals in extra time to knock Derby out of the FA Cup and move into the fifth round.
Wilfred Ndidi and Demarai Gray sealed the 3-1 win with a pair of brilliant strikes that finished off the replay against the second-tier Rams.
The victory came as a minor relief for champions Leicester who are one point above the English Premier League relegation zone after failing to win a league game this year.
Leicester had taken the lead a minute after halftime when Andy King headed home from close range.
Derby clawed their way back when Abdoul Camara's free kick took a wicked deflection on its way into the net.
Ndidi, a January signing from Racing Genk, put Leicester 2-1 ahead with a powerful run and bullet finish four minutes after being introduced at the end of normal time.
Gray completed the scoring with a mesmerising run that saw him weave through the Derby defence and side-foot home into the top corner.
Leicester, who along with Derby fielded a largely second-string side, visit third-tier Millwall in the last 16 on February 18.