Tottenham's Premier League title challenge suffered a huge blow as Leicester moved above them into second with an impressive 2-0 away win on Sunday.
Jamie Vardy's penalty and a Toby Alderweireld own goal moved the Foxes four points behind leaders Liverpool as for once Harry Kane and Son Heung-min failed to dig Spurs out of trouble.
Jose Mourinho's men were top of the table until a last-minute winner for Liverpool gave the champions a 2-1 victory on Wednesday but they are now six points behind Jurgen Klopp's team.
Leicester have six wins from seven away games in the Premier League this season and fans will begin to dream of a repeat of their 2016 title triumph.
"I thought over the course of the game we were outstanding and it was a very good win for us," Leicester boss Brendan Rodgers told Sky Sports.
But he added: "We have to start winning at home. The group is learning all the time and that's why we're nowhere near the finished product."
Klopp described Spurs as a "counter-attacking monster" but their deficiencies when not allowed the ability to break were exposed by Leicester's clever game plan.
The Foxes did not leave themselves exposed and posed the greater threat in transition.
A cagey first half of few chances saw James Maddison's long-range shot well held by Hugo Lloris, while Kane headed over Son's corner.
But Tottenham were undone by a moment of madness by Serge Aurier in the closing seconds of the opening period when he barged into Wesley Fofana just inside the area.
A VAR review was needed before referee Craig Pawson pointed to the spot and Vardy drilled home his sixth spot-kick of the league season.
- Bale disappoints -
Mourinho saw enough in the first 45 minutes to throw on Gareth Bale for the second half -- his first Premier League appearance since early November.
But in keeping with the Welshman's second spell in north London since rejoining on loan from Real Madrid, Bale struggled to make an impact.
Only a few millimetres denied Leicester a second in a bright start to the second half for the visitors as Maddison latched onto a ball over the top from James Justin and fired beyond Lloris, only for a VAR review to rule the goal out for offside.
Mourinho had sacrificed Tanguy Ndombele to bring on Bale and then lost his other midfield creator, Giovani Lo Celso, to a hamstring injury.
Lucas Moura replaced the Argentine to form a front four alongside Kane, Son and Bale, but Spurs became disjointed and were easily picked off by the Leicester counter-attack.
Tottenham inflicted more damage on themselves for the second goal as Vardy's header at the back post was turned into his own net by Alderweireld.
Kasper Schmeichel produced a sensational stop to deny Son at the back post, which would have given Spurs a lifeline 20 minutes from time.
Leicester should have won by an even more comfortable margin as Youri Tielemans blazed over and Harvey Barnes saw appeals for a second penalty turned away.
But two goals were enough for Rodgers to get the better of Mourinho for the first time in his managerial career and show that Leicester deserve to be taken seriously as contenders for a top-four finish.
"It is not a good week in terms of results," said Mourinho. "We could be here as the ones that broke Liverpool's record at Anfield and going into this game on a high.
"We started this game from the low of that disappointment and not getting what we deserved from that match, but Leicester also lost in their last match but came with a positive attitude. It's a game that we've lost with the penalty and the own goal."