The young striker's delightful chip from the edge of the area in the 55th minute was worthy of any stage and certainly worthy of maximum points in this FA Premier Reserve League encounter at the plush Walkers Stadium.
It capped a memorable few days for the 18-year-old who scored his first goal at this level at Chelsea last Monday before making his Premiership debut against Liverpool on Sunday.
Colin Calderwood's men lined-up with Slabber as a lone attacker supported by Jonathan Blondel and Rohan Ricketts and Chris Perry returned in a back three.
Neither side found any real cohesion in the opening exchanges as some occasional good approach work from the home side ran into the brick wall of Perry and Alton Thelwell.
Foxes had the first sight at goal as Chris O'Grady's curler popped up off the surface but Neil Sullivan smothered well.
The ever-willing David Galbraith caused a few problems down the left flank and Blondel flashed a ball across the six-yard line that was somehow poked to safety by a City defender.
Jon Stevenson had the best chance in the 33rd minute as Thelwell was caught out and the nippy striker suddenly found himself through on Sullivan. If anything he had too much time and the keeper was too cunning for him, reading his intentions and palming a close-range effort wide.
Spurs started the second half with more intent and Slabber's touch of class arrived within 10 minutes of the restart.
It all started with Galbraith's determination to win the ball back - he did so twice - before Blondel slipped two tackles and fed Slabber in the left channel of the area. He still had plenty to do but produced a delightful chip with his left foot to leave Paul Murphy clutching at air as the ball nestled into the far corner.
Dean Marney soon curled a free-kick inches wide and Mark Hughes bravely headed wide from another Galbraith cross as we started to get on top.
John Sutton, a former Spurs trainee released earlier this season, arrived as a substitute for Foxes on the hour but both he and Stevenson were left to feed off scraps as Perry snapped away at their heels.
Mark Yeates added a bit of pace and trickery to the procedings late on and Murphy knew little in tipping his fierce drive over three minutes from time.
Line-ups: Leicester City: Murphy, Ashton, Campbell, Heath, Tozer, Doyle, Deen, Butcher (Mortimer, 70), Stevenson, O'Grady (Sutton, 60), Larvin. Unused subs: Logan, McGavigan, Matthews.
Spurs: Sullivan, Marney, Henry, Toda, Thelwell, Perry, Hughes, Blondel, Slabber, Ricketts (Yeates, 81), Galbraith. Unused subs: G Kelly, Malcolm, Foster, Wettner.
Jamie Slabber's magical March continued with moment of Premiership class to win Wednesday's reserve clash against Leicester City.