Wanya Marcal-Madivadua opened the scoring in Borehamwood, but second-half goals from Zach Awe and Nathan Butler-Oyedeji handed the points to the Gunners.
Following defeat to Chelsea on Monday, Ben Petty opted for two changes to the XI for the visit to Meadow Park, with Ethan Fitzhugh and Kian Pennant coming in for Ronny Nelson and Deniche Hill. Both had impressed from the bench against the Blues.
The visitors began on the front foot, winning an early corner before Khanya Leshabela, making his second start since returning from a loan spell at Crewe Alexandra, went on a marauding run which forced another set piece. It came out to Brandon Cover, but his shot was straight at Hubert Graczyk.
Leicester were rewarded for their sharp start when a short corner routine saw Tawanda Maswanhise’s cross turned in from close range by Marcal-Madivadua on just his second start since returning from injury.
The momentum was briefly stopped by another injury, however, with Fitzhugh forced off and Hill coming on just a quarter of an hour into the contest.
Chituru Odunze in the Leicester goal, meanwhile, was rarely troubled early on. Even when Gunners captain Matt Smith whipped in an inviting free-kick, no one was able to find a touch to turn the ball towards goal.
Charles Sagoe then found Nathan Butley-Oyedeji, whose effort was blocked by Ben Nelson. Butlry-Oyedeji returned the favour moments later, but once again there was a block in the way, this time skipper Paul Appiah.
Continuing to stand firm, Ethan Nwaneri’s shot was stopped in its tracks by Joe Wormleighton, before Butley-Oyedeji got in behind, requiring Odunze to race out and make himself big to save.
The chances were now flowing for the home side, though, and Butley-Oyedeji tried to turn provider for Amario Cozier-Duberry, who curled a shot narrowly wide of the far post.
Arsenal remained in the ascendency during the opening exchanges of the second half, too, with Sagoe finding Nwaneri, but a smart close-range stop from Odunze kept the Gunners out.
Sagoe took aim himself soon after, with Nelson in the way, and Cozier-Duberry came even closer to a leveller from a left-footed strike which came back off the upright.
Still within the first five minutes of the second period, Hill broke away into the Arsenal box after winning back possession high up but was unable to test Graczyk.
The home side’s pressure told just before the hour-mark, from Smith’s corner, which was turned home by Zach Awe, whose header hit the crossbar before going over the line. Leicester responded with a change – Bayli Spencer-Adams was introduced, with Cover making way.
City might have gone back in front had K. Pennant connected with Marcal-Madivadua’s low cross, while Odunze was called into action sat the other end, holding on to substitute Catalin Cirjan’s shot.
The visitors briefly thought they had retaken the lead when Marcal-Madivadua had the ball in the net for a second time, converting Flynn's cross, but the offside flag went up to keep the scores level.
In an increasingly frantic encounter, Cirjan had a golden opportunity to hand Arsenal the advantage, collecting Butley-Oyedeji’s pass inside the penalty area, only to find Odunze in the way once more.
It was inspired stuff from the ‘keeper and was more to come, able to keep out Sagoe’s strike despite a wicked deflection. B. Nelson reached the rebound before Butley-Oyedeji could turn it home as the Foxes battled away.
There was to be a winner for the hosts, however. Cozier-Duberry’s shot was blocked, it fell kindly for Butley-Oyedeji to finish, sending the ball underneath Odunze’s grasp.
As Leicester through bodies forward in an attempt to level, spaces opened up and Hill made a last-ditch block on the line to stop Cozier-Duberry adding a third. There would be a final chance for substitute Terell Pennant, but his shot was straight at the ‘keeper and defeat was confirmed.
Major moment – A late winner
An even contest looked to be heading for a draw, and earn Leicester a much-needed point on the road, until Nathan Butley-Oyedeji pounced in the 85th-minute to claim victory for the Gunners.
Who impressed? – Odunze’s saves
Despite the end result, there were plenty of promising individual performances from Foxes players, particularly in the first half, but Chituru Odunze stood out in the second with some excellent saves.
Where do we stand? – 13th in PL2
City remain 13th in the division following the result, with nine points from 13 games.
Coming up – Man City (H)
Next up in Premier League 2 Division 1, Leicester's youngsters host Manchester City at LCFC Training Ground on Friday 20 January (7pm GMT kick-off).
The details...
City: Odunze; Wormleighton, Appiah (c), B. Nelson (T. Pennant 87’), Flynn; Cover (Spencer-Adams 60’), Leshabela, Marcal-Madivadua; Fitzhugh (Hill 15’), Maswanhise, K. Pennant.
Subs not used: Doherty, Godsmark-Ford.
Goal: Marcal-Madivadua 10’
Photos: David Price/Arsenal FC.