Leicester produced a superb display in their first game following the sacking of Claudio Ranieri, moving out of the Premier League bottom three as two goals from Jamie Vardy and a Danny Drinkwater strike saw off Liverpool.
It was a much-improved display from the Foxes under caretaker boss Craig Shakespeare, who took over after the departure of the man who led them to last season's remarkable title triumph.
The first strike was straight from the 2015-16 playbook as Vardy collected Marc Albrighton's precise long pass before racing clear and finishing low past Simon Mignolet to score his second goal in a week.
The second was an absolute cracker from Vardy's England team-mate Drinkwater, who showed superb technique to lash home his first goal of the campaign from outside the box following a clearance from a long throw.
And Vardy sealed the win with a glancing header from Christian Fuchs' cross in the second half before Philippe Coutinho stroked home a consolation goal.
The goals were the first the Foxes have scored in the league in 2017 and ended a run of five straight top-flight defeats in spectacular fashion.
Liverpool - who would have climbed to third with a victory - have now lost five of their past seven matches in all competitions.
Ranieri's name was everywhere at the King Power - in pre-game conversations, on banners and in chants - as was his face, courtesy of paper masks worn by some Foxes supporters.
The 65-year-old Italian has left an indelible imprint on the club with last season's astonishing success.
However, the inconvenient truth for many is that he was overseeing statistically one of the worst title defences in English top-flight history - one that has left Leicester facing the prospect of become the first reigning champions to be relegated since Manchester City in 1938.
Amid suggestions the players had stopped playing for their former boss, there was an element of damned if you do win and damned if you don't in this game.
However, the need for victory was paramount and they were excellent from start to finish as Shakespeare drew a committed, energetic and ruthless display to improve his chances of steering the club to safety - and possibly succeeding Ranieri on a permanent basis.
The champions also have players in form. Vardy now has three goals in two games and Kasper Schmeichel remains an authoritative presence in goal, as he demonstrated with two big saves to deny Coutinho and Emre Can in the first half and Adam Lallana after the break.
Deja vu for Liverpool
While Leicester have embarked on a demanding February comprising five matches, Liverpool have taken to the field just twice this month and came into this game off the back of a 16-day break, during which they took a training trip to La Manga in Spain.
But instead of looking refreshed, the Reds looked rusty throughout and were simply unable to make an impression on a night when they were always likely to be second on the bill.
Just over 12 months ago, Jurgen Klopp's side were undone on this ground as a Vardy-inspired Leicester consigned them to a defeat that left them 16 points off top spot in eighth.
They are now 14 points behind leaders Chelsea in fifth but look as far away from challenging for the title as they did in 2016.
Goalscorer Coutinho was their only consistent attacking threat, while the defence continues to look shaky - especially with Lucas masquerading at centre-back - and their midfield lacked the industry and bite to compete in the absence of injured captain Jordan Henderson.
They now have a real challenge on their hands if they are to finish in the top four and seal a return to the Champions League next season.
Man of the match - Jamie Vardy (Leicester)
What the managers said
Leicester caretaker manager Craig Shakespeare : "I could see in their eyes that they were up for the fight in the warm-up.
"The professionalism of the players has never been questioned by me. Having taken training with them, I know the the criticism has hurt and perhaps there was a little more fire in the belly because of that.
"They know they are guilty of underperforming - but this is only one result and we must build on that."
Liverpool manager Jurgen Klopp:"The language issues become a bit harder when you lose. It's hard to find the right words.
"It's not that Leicester were over-aggressive tonight, I think we were not physical enough.
"We knew how Leicester would play, go back to their roots. We could have done much better. We let them be Leicester of last year - that's our fault.
"We should get criticised. This inconsistency makes absolutely no sense."
Ndidi does Kante impression - the stats you need to know
Leicester have won all six of their Premier League games in which they have scored first this season, the only 100% record in the division.
Four of Liverpool's five Premier League defeats this season have been against clubs who started the match in the relegation zone (also Burnley, Swansea and Hull City).
Vardy's goal was Leicester's first in the top flight since 31 December, ending a run of 637 minutes without finding the net in the competition.
Coutinho's strike was his first in 12 games for Liverpool - he last scored against Watford in November.
Wilfred Ndidi made 11 tackles on Monday. Only former Leicester midfielder N'Golo Kante - now at Chelsea - has made more in a Premier League match this season (14 against Liverpool in January).
Only in 2012, when they picked up five points, have Liverpool won fewer points from their opening seven Premier League games of a calendar year than the six they have so far in 2017 (level with 1993).
Leicester host another relegation-threatened side on Saturday when Hull visit the King Power Stadium (15:00 GMT kick-off), followed by the second leg of their Champions League last-16 tie with Sevilla at 19:45 on 14 March.
Liverpool host Arsenal in Saturday's 17:30 kick-off and follow that up with another home game the following Sunday when Burnley travel to Anfield (16:00).