The young Foxes had tasted victory in successive league matches either side of Christmas but fell to defeat against the league leaders in Seagrave.
A penalty, converted by Reggie Watson, saw the Blues go ahead, but City equalised just before the interval; Alpha Diallo heading in a corner to restore parity.
Rising highest from a corner.
A second spot-kick, again sent in by Watson, saw the visitors back in front, before a second-half hat-trick from Ibrahim Rabbaj ensured the points would head to the capital.
Firstly firing home into the bottom corner, he doubled his tally with a curling strike and completed his hat-trick in injury-time with a low finish.
Leicester now sit fourth in the standings and welcome Reading to LCFC Training Ground on Saturday (12pm kick-off).
Back in Seagrave this weekend.
The details…
City: Marson, Lawrence, Simons, Manyumba, Diallo, Adedeji, Anugo, Boothe, Hutchinson (Aideed 63’), Corden (Fletcher 46’), Owusu (Colangelo-Allen 79’)
Unused subs: Stretton, Dignum.
Goal: Diallo 37’.