Diego Costa scored the opening goal as Chelsea ran out comfortable 2-0 winners but were made to work hard for it in the end against a plucky Leicester City side.
The Blues flattered to deceive in the first half, and must have got a verbal kick up the backside by Jose Mourinho at half-time.
When the same 11 reappeared after the break, it was a different Blues on show. They raised their tempo and put Leicester under immense pressure.
Costa finally broke their hearts.
Chelsea opened their campaign at Stamfprd Bridge will two of their summer signings, Diego Costa and Cesc Fabregas in the starting line-up, Felipe Luis was on the bench while returning loan goalkeeper Thiabaut Courtois remained between the sticks.
The significant substitute was that of Didier Drogba ahead of Fernando Torres.
What did that
As one would expect, Chelsea started the game on the front foot with Kasper Schmeichel the busier of the two number one.
An Oscar shot, deflected by Liam Moore for a corner and an Andre Schurrle drive that inched over Schmeichel's crossbar defined the first five minutes.
New boys Leicester, playing 4:4:2:1, with the emphasis on counter-attacking, whenever possible were content to sit back early on and soak up the pressure.
Courtois did get his hands to the ball on the 12 the minutes, simply picking up a speculative shot from Jeff Schlupp..
A swift break by the visitors on 18 minutes saw Branislav Ivanovic make a desperate dive to clear a Riyard Mahrez right sided cross which seemed destined for the head of David Nugent at the far post. Ivanovic's intervention, spared Chelsea blushes.
Jose Mourinho, perhaps sensing that his players had taken the foot off the gas, looked decidedly unhappy and jumped off the bench to prowl his technical area.
At one point, he appeared to lambast Costa for a lack of effort.
And it was well justified, as on 32 minutes, a sluggish Gary Cahill allowed Mahrez time and space to left fly with a venomous left-footer from just outside the Chelsea penalty area. Courtois did well to dive to his left to smother the shot.
So desperate were the Blues to break the deadlock, and with frustration mounting, that when Costa fell in the penalty area under a fair challenge from Wes Morgan, after a weaving run by Eden Hazard, Mourinho flung his hands out demanding a spit kick, along with 40,000 other fans. Referee
Lee Mason did not even dignify the chants with a response. To be fair to Costa, he just got up and got on with it.
With three minutes to go from the break, Mourinho had had enough and walked off away from the dugout and down the tunnel.
Neither manager changed any personal at half-time,
Leicester boss Nigel Pearson, clearly the happier so leaving things alone, while Mourinho giving this 11 a chance to rectify the situation.
Within three minutes, they almost go the chance. Oscar first curled a beauty of a right-foot from the edge of e penalty area which beat Schmeichel but rebounded off the base of his right post. Thirty seconds later and The goalkeepe produced another diving save to his right to beat out a powerful Ivanovic header that seems destined for the top left-hand corner of the net.
A flashpoint occurred on 50 minutes when a very late challenge by Dean Hammond on Schurrle resulted in the Leicester man getting a yellow card.
Nugent then almost scored when a quick breakaway saw Hammond feed the striker in the left.
He struck a beauty of a left footer bit Cpurtois, seemingly going the wrong way, stuck out a right boot and kicked it away to safety.
Schurrle then raced up the other end and was unlucky with a curler of his own which inched wide of Schmeichel's crossbar.
A dismissed claim for another penalty and a blaster of a shot by Ivanovic that Schmeichel brilliantly topped away livened the crowd but also left Chelsea exposed to a counter-attack. And that what happened a minute later on 54 minutes, which saw Nugent run free onto the Chelsea goal. Courtois earned his stripes by again thwarting the striker, this time it was his left leg that deflected the ball away.
Schmeichel was soon in action again in a see-sawing period of play, which saw Ivanovic play in Fabregas on the right. the ex-Arsenal midfielder attempted a delicate chip but Schmeichel got a hand to it to push the ball over the bar.
A Mourinho change was inevitable with Ramires about to come on for Schurrle, but not before the Blues took the lead.
Oscar fed the impressive Ivanovic on the right. The Serbian defender cut the ball back, dropping two Leicester players in the process with his dexterity. He thrashed the ball across the six-yard box when Costa, up to now a peripheral figure, chested the ball down, and toe-poked the ball under the advancing Schmeichel and into the back of his net.
That was Costa's second goal of the season after his strike in the opening fixture at Burnley on Monday night.
March Albrighton came on for Mahrez on 68 minutes for the visitors with Willian entering the fray a minute later, replacing Oscar.
Hammond limped off with what looked like a thigh problem to be replaced by Gary Taylor-Flectcher with 17 minutes left.
With Didier Drogba about to come on, the Blues scored their second on 77 minutes. Fabregas set up Hazard on the left, the Belgium midfielder, cut in and sent a swift, low right-footer past the prone Schmeichel.
A minute a later and the man who scored the winning penalty kick in May 2012, to secure Chelsea's Champions League victory - Didier Drogba, returned to the fold and replaced Costa to tumultuous applause from all around the ground. Even Roman Abramovich, stood up and applauded - revealing, it had to be said, sweaty armpit stains on his shirt in the process.
Pearson's last throw of the die to retrieve a seemingly lost cause, saw on 84 minutes, Chris Wood replace Leonardo Ulloa.
Willian almost produced the goal of the game, when, with a minute left he picked the ball up inside his own half, cantered forward and unleashed a blockbuster of a shot from 30-yards out which swerved in mid-air but did not fool Schmeichel, who produced a brilliant save.
The three points will be a welcome relief and it's two wins on the spin - The Blues go up to Everton next weekend hoping not to slip up this season like they did last season.
Teams: Chelsea, Courtois, Ivanovic, Fabregas, Oscar, Hazard, Schurrle, Costa, Matic, Cahill, Terry, Azpilicueta
Subs, Cech, Luis, Zouma, Ramires, Drogba Mikel, Willian
Leicester City, Schmeichel, De Laet, Konchesky, Morgan, Hammond, King, Sxhlupp, Moore, ulloa, Mahrez, Nugent
Subs, Hamer, Albrighton, Hopper, Taylor-Fletcher, Knockaert, Wasilewski, Wood
Referee: Lee Mason