Tottenham were left ruing a host of missed chances as Leicester held out to move into the top half of the table with victory at the King Power.
A deft lob from Jamie Vardy and a curling shot from Riyad Mahrez gave the Foxes a healthy half-time lead.
Christian Eriksen contrived to volley wide from six yards out before Harry Kane rifled in with 12 minutes to go.
Fernando Llorente then stabbed over the top from close range as the visitors hunted an equaliser in vain.
The hosts rode their luck to the end – with referee Anthony Taylor waving away a strong injury-time penalty claim as Danny Rose went down under Wilfred Ndidi’s challenge – but emerged with all three points from only 37% possession.
Claude Puel was sacked by Southampton at the end of last season
The victory is the biggest result since Claude Puel took charge and the Frenchman has amassed a quietly impressive record in his first month on the job.
The Foxes’ only defeat in his five league matches came to runaway leaders Manchester City and they have edged up from 14th up to ninth over that time.
Leicester 2-1 Tottenham: Claude Puel celebrates ‘fantastic game’
This win was straight from the 2015/16 title-winning template.
Vardy was permanently poised on the last defender’s shoulder or scampering down the channels. Wes Morgan twice came close with headers as Tottenham struggled with his physicality from set-pieces. Marc Albrighton hustled and harried as well as providing silver-service delivery into the penalty area.
Mahrez was still short of the sort of form that secured the 2016 PFA Player of the Year award, but the Algerian’s enduring quality showed as he drifted off the right wing, past Jan Vertonghen and swept home the decisive goal just before the break.
Puel will know, however, that his predecessor Craig Shakespeare also sought to take Leicester back to the basics that won them the title, only to run out of momentum after initial success.
Tottenham’s position above Real Madrid and Borussia Dortmund in their Champions League group is no longer masking some serious stalling on the domestic scene.
Spurs have won just one of their last six games away from European competition, have lost as many league games as they did in the whole of last campaign and could well be seventh by the end of tomorrow.
For all his good work during his time at the club, Mauricio Pochettino’s tactics seemed to set his side up for Leicester’s counter-attacking sucker-punch.
A high defensive line left acres of space for Vardy to exploit, and Vicente Iborra and Ndidi had already aimed long balls over the top for the England striker before his sublime opener.
The Argentine was not helped by some shockingly poor finishing from his side.
Dele Alli – with three Premier League goals this season – should have beaten Kasper Schmeichel to level after Moussa Sissoko had been denied from a similar position in the first half. Worse was to come with the misses from Eriksen and Llorente.