Mark de Vries scored an injury-time winner as Leicester came from two goals down to defeat Tottenham in the FA Cup.
Jermaine Jenas put Spurs ahead from close range after Robbie Keane's header rebounded off the post, before Paul Stalteri's spectacular long-range goal.
Substitute Elvis Hammond scored just before the break and Stephen Hughes equalised with a deflected strike.
De Vries then struck the winner with a low shot past Paul Robinson from 12 yards to snatch a famous win.
Leicester seemed out of the match after falling 2-0 down in the 41st minute to a team fourth in the Premiership.
But Craig Levein had bravely brought on Hammond after just 35 minutes and reverted to a 4-4-2 formation - sparking a transformation in the home team.
And after reducing the deficit before the interval, the Championship side really attacked Spurs after break, rattling their Premiership opponents.
Leicester striker De Vries was a thorn in Tottenham's side throughout the match.
The 30-year-old saw a shot deflected wide and almost scored after intercepting a poor defensive header from Stephen Kelly in the opening phase of the contest.
Tottenham's 20th-minute opener came somewhat against the run of play, Jenas reacting quicker than the Leicester defence to the rebound after Keane had hit the woodwork.
Spurs then created a series of chances as Leicester struggled to contain Aaron Lennon, who used his blistering pace to reach the byline and whip in a series of dangerous crosses.
Rab Douglas saved from Keane with a fine one-handed parry before the Irishman smashed the rebound wide via the legs of a Leicester defender.
Keane, skipper for the day and full of running, then chipped the ball inches over Douglas' crossbar.
Stalteri's vicious top-corner strike five minutes before the break appeared to put the tie beyond the Foxes.
But substitute Hammond, who replaced Jo Hamill, gave Leicester a lifeline when he scored three minutes after Stalteri's goal, converting from close range after Steadman had picked him out with a header at the far post.
Leicester almost equalised in the first minute of the second half, only for Robinson to thwart Hughes.
Kelly could have restored a two-goal lead for Spurs after being put through on goal but he looked unsure and his shot, when it finally arrived, flew well wide.
His profligacy in front of goal was punished when Hughes' crisp strike from the edge of the area defeated Robinson via a crucial deflection off Michael Dawson.
De Vries went close to a third with a right-foot strike from 18 yards but, with a replay beckoning, the striker did find the net to seal a dramatic comeback for the home side.
Leicester: Douglas, Stearman, Maybury, Johansson, McCarthy, Hamill (Hammond 35), Smith (Kisnorbo 90), Gudjonsson, Williams, Hughes, de Vries.
Subs Not Used: Henderson, Hume, Dublin.
Goals: Hammond 44, Hughes 57, de Vries 90.
Tottenham: Robinson, Stalteri, Kelly, Gardner, Dawson, Lennon (Tainio 87), Brown (Defoe 70), Carrick, Jenas, Keane, Rasiak.
Subs Not Used: Cerny, Pamarot, Routledge.
Goals: Jenas 20, Stalteri 41.
Ref: S Bennett (Kent).