They faced rivals Derby County
Leicester City are into the last-16 of the FA Cup after beating Championship Derby 3-1 in their fourth-round replay.
The two teams finished 1-1 after 90 minutes, before goals from Wilfred Ndidi and Demarai Gray sealed the win.
The original fourth round tie had finished 2-2 at Pride Park on Friday, January 27th, forcing the rivals into a replay.
However, neither side could not be separated yet again after 45 minutes.
But on 46 minutes, Wales midfielder headed Leicester in front after a Gray cross was diverted on by Marc Albrighton.
However, Derby fought back at the King Power Stadium as Abdoul Camara found the net with a free kick.
That forced extra time with no further goals in the 90 minutes.
Leicester, who are battling against relegation just months after winning their first Premier League title, found something extra in the next period.
Ndidi's brilliant strike four minutes into extra time put them 2-1 up and Gray sealed victory 10 minutes later to put the game to bed.
Leicester will now take on Millwall next.
In the lead up to tonight's game, Foxes manager Claudio Ranieri had received a vote of confidence from the Leicester board after a difficult season so far.
In a statement, the club had said: "In light of recent speculation, Leicester City Football Club would like to make absolutely clear its unwavering support for its First Team Manager, Claudio Ranieri."
"While there is a collective appreciation from everyone at the Club that recent form needs to improve, the unprecedented success achieved in recent seasons has been based firmly on stability, togetherness and determination to overcome even the greatest of challenges."
"The entire Club is and will remain united behind its manager and behind its players, collectively and firmly focused on the challenges ahead."