The Blues were ahead inside seven minutes when Nemanja Matic flicked on Eden Hazard's corner for Diego Costa to smash home.

A David Luiz free-kick struck the post, before Pedro played in Hazard, who rounded Kasper Schmeichel to slot in.

Luiz hit his own post when clearing a cross, but Victor Moses' finish after a one-two with substitute Nathaniel Chalobah completed the scoring.

Leicester, who left Riyad Mahrez on the bench for the first time in 36 league games, failed to register a shot on target as they struggled to cope against Chelsea's aggressive pressing and quick passing.

Defeat leaves Claudio Ranieri's side with eight points from their first eight games - the joint second lowest haul by a defending Premier League champion, along with Chelsea's team of last season.

Relive Chelsea v Leicester
The Kante derby

Since joining Chelsea from Leicester this summer, N'Golo Kante has found himself doing slightly less of the defensive work that established him as such a prized midfielder at the King Power Stadium.

But he continues to enjoy the gift of being in the right place at the right time and this was another excellent performance from the France international - who is clearly missed by Claudio Ranieri's side.

However, much of Chelsea's success in stifling the visitors came courtesy of their wing-backs. When Marcos Alonso - making his home debut - harried Danny Drinkwater high up the pitch to win the ball back and deliver a dangerous low cross, he was repeating the pattern set by Moses on the opposite right flank.

Instead we saw the other side of Kante's game. The 25-year-old would have scored Chelsea's third had it not been for Foxes captain Wes Morgan, who made a brilliant block after a Costa cross spilled off Schmeichel's legs to leave the goalmouth exposed.

And his perfectly weighted through ball deserved a better finish from Moses, who eventually did settle the points for certain when latching on to a delightful flick by 21-year-old English midfielder Chalobah - making his senior home debut after six loan spells away from the club.
Don't believe the rumours

On Thursday, several bookmakers suspended betting on Chelsea boss Conte being the next Premier League manager to lose his job.

The Italian laughed off the rumours in his news conference on Friday -"I am trying to find out who put the money on" - but some may have wondered if there would be a sign of weakness in his side's performance.

There was not. Chelsea began with real swagger and Costa's early goal was the end product. The Premier League's top scorer gambled on a late move to the back post and, as Morgan did not stay with him, was left with an easy finish for his seventh of the campaign. It took the 28-year-old Spain striker until January to reach that total last season.

The dipping Luiz free-kick that crashed against the post would have been a fitting second, so when Hazard found himself through on goal after a slightly lucky bounce it was hard to deny a 2-0 lead was deserved. The Belgium winger showed superb composure for his third goal from eight matches this season - compared to four from 31 last term.

And one of the finest flourishes came from Conte himself. There was a huge round of cheers from the home crowd when he brilliantly trapped a misplaced long pass that plummeted down into his technical area.

The fans will have found it hard not to have been incredibly impressed by their team's performance - especially after what they witnessed over 2015-16.
Man of the match - N'Golo Kante (Chelsea)

What they said

Leicester manager Claudio Ranieri: "When you concede a goal from a corner again it is clear: you come to Chelsea and your attention must be at the maximum. We made mistakes. We tried to react and the second half was much better. Now we must react because we have the Champions League on Tuesday.

"If we scored the goal when we create a chance we can re-open the match. But our approach to the match was not good. Maybe we were a little nervous.

"It is better that this happens now and we can react than at the end of the season. We must concentrate more.

"We miss him [N'Golo Kante] - but we have to play better."

Chelsea manager Antonio Conte: "It was a good game. From the start I asked them to play well with intensity and to try to do what we are doing in training.

"I am very happy because I had a good reply. This is the best game for us. I saw good commitment. When you work hard it is important to have a good performance.

"In the week, we tried a lot to find a solution that gave us more compactness. For this team and squad this system is the right fit. The coach must understand and find the right suit. We are like a tailor."

The stats you need to know

    Leicester are the fourth reigning top-flight champion to lose their opening four away league games - and the first since Blackburn in 1995-96.
    Costa has had a hand in 50 Premier League goals for Chelsea (39 goals, 11 assists) in just 62 games.
    Since his debut in August 2012, Hazard has scored more Premier League goals than any other midfielder in the division (44).
    Leicester have failed to score in three Premier League games this season, the same number as in the whole of 2015-16.
    Matic (three assists in eight appearances) has made more Premier League assists this season than in the entire 2015-16 campaign (two assists in 33 apps).

Analysis

Former Chelsea winger Pat Nevin on BBC Radio 5 live:

"It's a very worrying time for Leicester. They've found out that getting to the top is one thing but staying there is quite another."

Former Leicester captain Matt Elliot on BBC Radio Leicester:

"It was a very, very bad day at the office for Leicester. Chelsea looked likely victors from the absolute start."
What's next?

Leicester return to the Champions League on Tuesday with a home match against FC Copenhagen of Denmark (19:45 BST kick-off), before hosting Crystal Palace in the Premier League on Saturday (15:00).

Chelsea entertain Manchester United in the Premier League at 16:00 next Sunday.