High-flying Leicester overcame bitter East Midlands rivals Derby to maintain their 100 per cent record in their impressive new fortress the Walkers Stadium.
Honours were even in a hard-fought first half, but after the interval City found an extra gear to lead Derby floundering in their wake.
Leicester were determined to unsettle Derby from the start and uncompromising tackles saw three City players shown yellow cards inside the opening 20 minutes.
Brian Deane headed a ninth minute chance against the bar and then missed a simple chance when one to one with the keeper.
But the visitors refused to be rattled and broke through after 22 minutes to grab a shock lead.
Rob Lee crossed from the right to the far post where Chris Riggott headed across Ian Walker and into the far corner of the net.
Undeterred, Leicester were level within five minutes when James Scowcroft's cross from the right was headed home by Muzzy Izzet.
On the hour mark Walker showed lightening reactions to beat out an Adam Bolder goalbound shot, but after that it was City who took command.
After several narrow misses they finally broke through 12 minutes from the end when Jordan Stewart found Deane who had time to compose himself before beating Mart Poom with a low curling shot from 16 yards.
Poom then denied Callum Davidson with a brilliant save before Leicester put the game beyond Derby with three minutes left when Deane flicked on a long clearance from his keeper for Paul Dickov to fire home an unstoppable shot from 15 yards.
City boss Micky Adams said: "I thought Muzzy Izzet was terrific today. I can't praise the man enough. He is Premiership class.
"Brian Deane is 34 and we keep wheeling him out of the treatment room. Even if he is only 70 per cent for some matches that is good enough at this level. If he was 100 per cent he would be simply awesome.
"If we are still near the top in January when the transfer window reopens I fully expect the Premiership piranhas to pounce, but we will deal with that when it comes."