Jose Mourinho???s men found themselves 1-0 down at half-time to a Marc Albrighton goal but they came out with much more pace and purpose after the break and goals from Didier Drogba, John Terry and Ramires turned the game on its head.
The result means that a Chelsea victory against Crystal Palace on Super Sunday will guarantee them at least an 80-point haul, meaning they can???t be caught at the top.
Meanwhile, Leicester, who were good value for their first-half lead, remain outside the relegation places by one point.
Mourinho handed a surprise start to Petr Cech, to replace Thibaut Courtois, who was not 100-per-cent fit according to the Chelsea boss. Drogba was also brought in to add more physicality to their attack but it was the hosts who started with the most muscle.
Esteban Cambiasso picked out Leonardo Ulloa with a fantastic first time pass that sent the striker through on goal but Ulloa’s first touch was poor and the ball squirmed away from danger.
It was Leicester that continued to look the more threatening in possession as Chelsea struggled to find any tempo to their game.
Paul Konchesky forced a smart save low down to his right from Cech on 41 minutes and somehow Chelsea survived a goalmouth scrambled that saw Cambiasso and Albrighton go close.
Albrighton hadn???t scored a Premier League goal for three years before this clash but you wouldn???t have thought it judging by the way he stroked home Leicester???s opening goal on the stroke of half-time.
Jamie Vardy did the hard graft down the left wing and sent over a delicious cross along the wet turf which confused Azpilicueta, who slipped, and Albrighton was the man on the spot to fire home.
Strong words must have been said in the Chelsea dressing room at half-time and they came out a different animal in the second-half; full of pace, full of determination.
It took them just three minutes to draw level and it came from a man who has made a career out of scoring big goals at big moments.
Drogba showed great striking instinct to find half a yard inside the area and Branislav Ivanovic found the striker with a fine cross, which he swept home confidently.
Leicester huffed and puffed but failed to deal with the revitalised Chelsea midfield, spearheaded by the brilliant and energetic Willian.
Drogba went close to doubling his tally with a couple of wayward shots but it was his skipper, Terry, that edged Chelsea in front with 11 minutes left.
Gary Cahill powered a header towards goal from a Cesc Fabregas corner and although Kasper Schmeichel tipped his header away, Terry was on hand to poke home from two yards.
The Chelsea fans were now in full voice, sarcastically chanting ???boring, boring, Chelsea??? in response to Arsenal???s fans chants after the 0-0 draw on Sunday.
There was nothing boring about their third goal though as they turned on the style.
Fabregas danced his way down the right flank and cut the ball back for Ramires, who still has a lot to do, but he found the top corner with a bullet of a strike from the edge of the area.
???Boring Chelsea??? are on the cusp of a first title for five years.??