Following successive 1-1 draws with Norwich City and Reading early in the campaign, the young Foxes were beaten by Brighton & Hove Albion and Fulham over recent weeks.
However, the visit of the Gunners to Belvoir Drive proved to be a much more enjoyable occasion for City's youngsters as captain Sidnei Tavares sealed all three points.
Leicester's starting XI included appearances for Tavares, Terell Pennant and Dempsey Arlott-John, all of whom have represented the Club's Development Squad.
American goalkeeper Chituru Odunze, meanwhile, made another outing at City's training ground against a typically talented Arsenal line-up.
A tight encounter was settled in the 62nd minute as Adam Leathers located the run of Tavares, before the Portugal youth international applied a finish to put Leicester ahead.
Following their maiden win of the new season, the young Foxes climb to eighth in the 12-team U18 Premier League South standings with five points from five matches.
On Saturday, meanwhile, they travel to Swansea City (11am BST kick-off) before later facing Manchester United at the Aon Training Complex a week later (12pm BST kick-off).
The details...
City: Odunze; Flynn, Sams, D. Gyamfi, Gbadebo; Fitzhugh, Pennant, Tavares (c), Leathers; Arlott-John, Ewing
Subs not used: Aisthorpe, Lane, J. Gyamfi, Loughlin, Russ
Goal: Tavares 62'