After a goalless opening 45 minutes in Seagrave, the Lilywhites edged ahead through captain Tye Hall before Malachi Hardy doubled Spurs' advantage with 20 minutes to play.
The third came from the penalty spot; Reiss Elliot-Parris converting it to confirm three points and leave Leicester seventh in the PL U18 table, having collected 31 points from 22 matches.
Another home fixture, against Southampton, is coming up at LCFC Training Ground on Wednesday morning (11am GMT kick-off).
The details...
City: Stretton, Aideed (Anugo 79'), Diallo, Adedeji (c), Simons (Jacklin 53'); Manyumba, W. Lawrence; Colangelo-Allen (Dignum 56'), de Lisle, Owusu; Fletcher (Boothe 79').
Sub not used: Hames.