Even with Jamie Vardy on a five-game goal drought, composed and controlled Leicester have enough quality to win.

Maddison's goal – his third in three outings – came just two minutes after VAR had overturned a penalty award for Chelsea when replays showed Jonny Evans' foul on Christian Pulisic came outside the box.

Defeat further dented Chelsea's top-four hopes and their indifferent form of two wins in eight league games keeps the pressure on boss Frank Lampard.

A summer spend of over £200million has failed to reap immediate rewards and they sit eighth, five points adrift of the top four.

The visitors never looked like troubling the Foxes and Lampard would have been furious when his expensive side paid the price for switching off twice to help the hosts to a sixth-minute lead.

First, they were slow to react to a quick free-kick and Tammy Abraham knocked Harvey Barnes' cross behind.

Then, when Marc Albrighton and Maddison combined for a short corner, the visitors were unprepared.

It allowed Albrighton to cross for Barnes, who miscued, and the ball fell for Ndidi to cut a half-volley in off the post from 20 yards.

Knowing victory would take them back to the top for the first time since November, the Foxes continued to push and Maddison clipped the bar 10 minutes later after Timothy Castagne's bustling run.

Kasper Schmeichel had to turn Reece James' driven effort over after 20 minutes but the visitors' flaws had been exposed early.

There was little suggestion they would recover, even if Callum Hudson-Odoi hit the side netting from a promising position.

By then Edouard Mendy had already turned Albrighton's speculative effort over as the Foxes hunted a second, while Barnes and Vardy remained constant dangers.

Vardy continues to nurse a long-standing hip problem but underlined his threat when he burst down the right and Mendy saved his attempted lob.

Leicester looked comfortable but Chelsea thought they had a lifeline six minutes before the break when Craig Pawson pointed to the spot after Evans tripped Pulisic.

Yet a VAR review correctly ruled the foul was just outside the area – Pulisic's momentum carrying him in – and Mason Mount blazed the free-kick over.

It proved crucial as the Foxes immediately doubled their lead.

From Kasper Schmeichel's goal kick the ball eventually fell for Albrighton and his clever lofted pass bounced over Vardy to Maddison.

The midfielder had been left unmarked and he comfortably beat Mendy from 15 yards for his eighth goal of the season.

The Foxes were far more complete than the work-in-progress visitors and the unmarked James Justin should have made it 3-0 four minutes after the break but headed Albrighton's deep cross wide.

Albrighton was also denied a goal by the offside flag and Mendy saved from Youri Tielemans but despite failing to grab a third the Foxes' victory was never in danger.

And when substitute Timo Werner – without a goal in the Premier League since October – did have the ball in the net, turning in Hakim Ziyech's free-kick with four minutes left, he was ruled offside.