Having trailed on the quarter-hour mark to a wonder-strike from County striker Romello Nangle, the young Imps responded well and after levelling courtesy of a sublime Conner Robinson finish, they were in front just seven minutes later when Rob Taylor made the most of a mistake from visiting ‘keeper Harry Andrews.
Taylor grabbed his second and City’s fifth shortly after the restart, prodding home after Andrews could only palm out a low Aaron Rice into his path and the lead was very nearly extended further when substitute Alex Simmons rattled the post.
A late second for Nangle made for a nervy close but the City teenagers held out to book themselves a home tie against Hartlepool United, who defeated Fleetwood Town 5-4 on penalties after their tie finished all square at one goal apiece.
The U18s went into this FA Youth Cup First Round Proper tie against Notts County at The 12th Imp Sincil Bank Stadium with teenage professionals Conner Robinson and Jordan Thomas both in the starting line-up.
City kicked off and were quickly on the attack with Thomas having a low effort palmed away by Harry Andrews and after the resultant corner was half-cleared, Ryan Leggett fired just off target from range.
With a greasy surface due to the heavy drizzle that was falling, some juicy early challenges were starting to go in, one such incident seeing Will Rawdon lucky to escape injury. The resultant free-kick ended us seeing Rob Taylor skip past his man but the ball clipped his shin before going out for a goal kick.
A City corner quickly followed before Thomas had a low skidding shot held by Andrews but the visitors responded with a goal out of the blue; striker Romello Nangle powering home a thunderbolt from 25-yards which gave Ollie Pannell no chance between the sticks.
The Imps looked for a quick response with Andrews at full stretch to claim a Thomas shot before the County stopper got behind a rasping Taylor effort. The visiting number one was helpless a minute later though as Robinson superbly turned his man before curling sublimely into the corner of the net to level matters.
Two minutes later the Imps edged themselves in front when, after Andrews failed to deal with a cross into the danger area, the ball ran loose to Taylor who produced a clinical finish from just inside the box.
The excellent response was fully deserved and with Andrews by far the busier 'keeper, he was forced to hold a low Thomas centre as the striker went in search of a third shortly before the half-hour mark.
City kept up the pressure with Thomas having a 25-yarder tipped over by Andrews for a corner. This was taken by Taylor and hit the post before Luke Weaver had a follow-up effort fly just wide.
A rare County attack, which ended up with Weaver dumping Kyle Dixon to the floor, led to a Malachi Lavelle-Moore free-kick which was claimed at the second attempt by Pannell. Robinson then had two shots blocked as City responded before the break came.
HT: Imps U18s 2 Notts Co U18s 1
Kameron Campbell and Elliot Hodge replaced Tyler Guy and Matthew Guest for the visitors before they got the second half underway.
It was the Imps who came out the brighter, winning a corner two minutes in but Andrews commanded his area well to claim under pressure from Weaver. The County 'keeper was left holding his head, however, shortly after as after he was unable to hold a low Rice effort there was Taylor to fire home his second of the game to make it 3-1.
Thomas came close to adding another five minutes later when a swift counter-attack ended up with the striker shaking off his man before drilling over. Taylor was then denied his hat-trick by a fine Andrews save following good work by Robinson.
County's Mitchell Clarke then wasted a great chance for his side when he blazed well over from inside the box and as the resultant goal-kick was pumped forward by Pannell, Rice was left grounded following a tough aerial challenge on the half-way line.
Glodie Bange for Ryan Freshwater was Notts' final change of the game as the clock ticked into its 68th minute and three minutes later his fellow sub Hodge was spoken to by referee Tommy Hollidge following a crunching challenge on Thomas.
Thomas went off shortly afterwards to be replaced by Alex Simmons and the Imps were forced to make another change nine minutes from time when Matt Bowles hobbled off injured. Josh Gibson was his replacement.
Simmons' first real impact saw him fire in a low drive which beat Andrews before crashing against the foot of the post and from the next break, Rice cut in from the right before firing wide from range.
Pannell saved well from a James Randall header as County responded but with a minute on the clock, Nangle nipped in as the City 'keeper clashed with Leggett for a ball over the top to head home. Pannell required treatment before play restarted.
City had four minutes of added time to see out and this they duly did to secure their place in the second round and a home tie against Hartlepool United, who defeated Fleetwood Town 5-4 on penalties after their tie finished all square at one goal apiece.
FT: Imps U18s 3 Notts Co U18s 2
City U18: Ollie Pannell, Nick Green, Will Rawdon, Kegan Everington, Luke Weaver, Ryan Leggett, Rob Taylor, Matt Bowles, Jordan Thomas, Conner Robinson, Aaron Rice.
subs: Kieran Walker, Matt Cotton, Charlie Brownlie, Alex Simmons (for Thomas 75), Josh Gibson (for Bowles 81).
goals: Robinson (20), Taylor (22, 51)
Notts Co U18: Harry Andrews, Ryan Freshwater, Tyler Guy, Matthew Crust, Liam Guest, Brad McGowan, Malachi Lavelle-Moore, Kyle Dixon, Romello Nangle, James Randall, Mitchell Clarke.
subs: Monty Parkes, Kieran Geldenhuys, Kameron Campbell (for Guy 46), Glodie Bange (for Freshwater 68), Elliot Hodge (for Crust 46).
goals: Nangle (15, 89)
Referee: Tommy Hollidge
Assistants: Ryan Goddard & Ryan O'Mahoney
Fourth Official: Mark Thomson