Neil Danns' early goal tightened Leicester's grip over Derby, who they have now beaten four times running. The neighbours started level on points, but Nigel Pearson's expensively-built team performed with the vibrancy of players who clearly still believe the season is replete with possibilities.
By contrast, Derby have now gone six Championship games without a win, scoring in only one, and they had a double reprieve in the last minute when Lloyd Dyer fired against post and bar in swift succession
Buoyed by their FA Cup success at Norwich, Leicester looked the more confident unit and it was no surprise when Danns arrived to side-foot his fourth goal of the season from Dyer's cross in the 16th minute. Leicester's passing had a precision Derby struggled to muster, and 10 minutes before half-time the home manager Nigel Clough was on the edge of the technical area, shouting and gesturing to try to spark his side into life.
But for all Leicester' s superiority, their lead was too slender for them to spurn chances, which was what David Nugent did in the 49th minute, scuffing his shot wide from six yards. Derby, perhaps amazed still to be in contention, produced a spell of pressure, albeit without seriously working Kasper Schmeichel.
Derby County (4-4-2): Fielding; Green, Barker, Shackell, Roberts; Carroll, Hendrick, Bryson (Robinson, 81), Morris; Tyson, Ball, (S Davies, 76). Substitutes not used Legzdins (gk), Buxton, Naylor.
Leicester City (4-4-2): Schmeichel; Peltier (Bamba, 72), Morgan, St Ledger, Konchesky; Marshall (Drinkwater, 79), Danns, Wellens, Dyer; Nugent, Beckford (Delfouneso, 72). Substitutes not used Howard, Kennedy.
Referee S Hooper (Wiltshire).