The midfielder curled in a free kick with 19 minutes left to leave the Foxes winless in their last 13 games.
Former Leicester loanee Harry Kane scored inside the first minute for Spurs but the Foxes rallied and Leonardo Ulloa levelled in the second half.
The striker also hit the post and Hugo Lloris saved from Riyad Mahrez and Jeff Schlupp but Leicester could not lift themselves off the bottom of the Barclays Premier League.
Ulloa and David Nugent were recalled to spearhead the hosts' attack with Jamie Vardy and Esteban Cambiasso dropped to the bench.
Tottenham, now just a point outside the top five, started Danny Rose and Benjamin Stambouli for Ben Davies and Ryan Mason with Kane, who spent four months on loan at the King Power Stadium in 2013, up front.
And the striker made an immediate impact when he opened the scoring after just 57 seconds.
Tottenham hit Leicester on the break with Nabil Bentaleb and Nacer Chadli, and the winger crossed for Kane to skip round the falling Wes Morgan and find the corner from six yards.
Kane's fourth goal in four games was devastating from Spurs but highlighted why the Foxes were bottom at Christmas.
The visitors were given an easy ride by the shell-shocked hosts with Kane shooting wide and Kyle Walker granted the freedom of the right flank.
There was little threat from Leicester until the 18th minute when Lloris palmed over Ulloa's 20-yard volley after Schlupp's driving run.
Danny Drinkwater then dragged wide from distance before Bentaleb wasted a golden chance to make it 2-0 on 32 minutes.
Eriksen played the Algeria international clean through but he had an awful touch as he reached the area which allowed Paul Konchesky to cover and clear.
It rallied the hosts and, after Ulloa had comically fallen over as he looked to shoot, Mahrez's driven effort was well saved by Lloris.
Tottenham were rocked and Ulloa should have levelled six minutes before the break but he smashed a four-yard header against the inside of the post after Mahrez's searching cross.
The Foxes were dominant and their persistence paid off three minutes into the second half.
Danny Simpson and Mahrez combined for the Algeria winger to cross low for Ulloa to turn in at the near post.
It had been coming and Mahrez almost completed the comeback when his 20-yard free kick smacked against the bar minutes later.
The Foxes' efforts warranted more and Lloris again saved from Schlupp before disaster struck for the hosts on 71 minutes.
Kane was fouled 25-yards out and Eriksen curled in an angled effort which bounced in off the post.
It was the Dane's seventh goal of the season and he has now hit four winners for Spurs this season.
The goal initially killed Leicester's spark but they regained their composure and Ulloa flicked a header onto the roof of the net.
Two half-hearted penalty appeals went unrewarded but Morgan should have levelled in the final minute.
The excellent Mahrez again found space on the right and his cross reached the unmarked Morgan at the far post but the skipper failed to get a clean connection and Lloris gathered to seal the points.
Source : PA
Source: PA