Coker was on hand to force the ball home from close-range sixty seconds after the expiration of the regulation 90 minutes having entered the field of play just a quarter-of-an-hour earlier as a substitute for the injured Sam Brogan. The former Bowers & Pitsea youngster had earlier scored twice for the U16s on an adjacent pitch, so the late effort completed a rather unique hat-trick.

Blues ended the game having fielded four schoolboys including Louie Arrowsmith and Adetayo Adedoja, who both started the fixture for Danny Heath’s team. Coker joined counterpart Jaden Crowhurst in being introduced late in the match, with Callum Taylor and Ahmet Biler the only second-years to complete the contest.

Southend should have taken the lead as early as the fourth minute when Arrowsmith’s superb through-ball was controlled by Adedoja. He rounded Charlie Walker in the Gillingham goal but was forced too wide to shoot. Nonetheless, his centre to the far post picked out Lambourne, who failed to add to the five goals he had scored in his previous two outings from just a few yards out.

Arrowsmith and Adedoja combined again five minutes later, with the latter dragging a shot wide following a left-wing cross, but by that time Callum Taylor had been called into action for the first time, making a fine parried save to keep out a headed attempt by Harry Laing following a free-kick.

It was the visitors who were controlling the early skirmishes, however, and Blues took the lead on 16 minutes. Bobby Unwin’s searing strike from an Adedoja assist had just been brilliantly tipped over by Walker when Biler’s inswinging corner caused panic in the Gillingham penalty area. The ball ricocheted around and eventually dropped over the goal-line, with defender Ergis Shala celebrating the final touch.

Taylor was immediately drawn into action to protect Southend’s lead, turning a Toby Bancroft header over at full-stretch, but Jimmy Wallace side-footed wide from Cameron Brown’s flag-kick at the other end as Blues sought to add to their advantage.

Instead, shortly after the half-hour mark, Gillingham restored parity. George Baker-Moran flicked the ball into the path of Bancroft and he sprinted clear of the Blues back-line before smashing a shot into the bottom left-hand corner of the net. Taylor got a glove to the ball, but he was powerless to prevent the goal.

The teenage Shrimpers responded well, and Unwin almost put them back in front straight from the restart as he drifted inside from the right touchline and drilled a 20-yard effort past Walker but into the side-netting. Unwin also fizzed an enticing centre across the six-yard box and Brown hooked over from close-range before the half ended with Gills defender Max Niblett slicing Biler’s cross inches past the frame of his own goal.

There was just time for Biler to drill the ball into Walker’s gloves from the ensuing corner, and Southend began the second period with the same attacking intent as Lambourne’s cross was cut out and Arrowsmith fired narrowly over from twelve yards out.

Despite Wallace being called upon to make a fine challenge in his own penalty area shortly afterwards, Blues were building momentum with Adedoja and Lambourne developing greater understanding up front. Twice in a couple of minutes Adedoja turned his marker from throws, firstly delivering a cross inches out of Lambourne’s reach and then setting up his strike partner for a fierce shot that Walker turned away with aplomb.

Gillingham responded with Taylor leaping to his left to push a Jimmy Witt effort away from goal and Brown and Shala then combining to clear a right-wing cross. Blues were restricted to an opportunity on the counter-attack, and it appeared that Adedoja had forced a mistake from Laing as he went down under pressure from the defender, but the referee waved away appeals for a penalty.

Blues were then dealt a sucker-punch as Bancroft clinically notched his second goal of the game to put the hosts in front. The forward superbly controlled a deep Ronny Nelson cross at the far post before arrowing his finish inside the bottom left-hand corner.

Lambourne nodded wide from a Wallace cross, but Southend were hit by another set-back on 75 minutes when skipper Brogan was injured whilst charging down a Gillingham clearance. Whilst Blues were reorganising Bancroft almost completed his hat-trick, but Taylor made a fine stop at his near post to keep out a thumping strike.

Coker replaced Brogan and Crowhurst took up a midfield berth in place of the impressive Arrowsmith, and Southend almost reaped the rewards in the 83rd minute when Biler’s delivery was flicked on by Coker and Lambourne tried to lob Walker, but he failed to provide sufficient weight to his execution.

Unwin smashed wide whilst off-balance and was then denied by a desperate defensive block and, as the match moved into stoppage time, it looked as though the visitors would be thwarted. But Biler was brought down besides the left touchline and he brushed himself down to send the free-kick to the far post. Tommy Davis knocked the ball down and Coker was on hand to sweep it home and spark jubilant scenes.

Blues remain in a seven-way battle for the final three places in the Merit League One qualification process following the result, although four of the side’s remaining fixtures are at Boots& Laces, beginning with the visit of AFC Wimbledon on Saturday (kick-off: 10:30am).

Southend United U18s: Callum Taylor, Tommy Davis, Ahmet Biler, Sam Brogan (Kenny Coker, 75), Jimmy Wallace, Ergis Shala, Louie Arrowsmith (Jaden Crowhurst, 81), Cameron Brown,  Adetayo Adedoja, Tommy Lambourne, Bobby Unwin. Substitutes not used: Jamie Grossart, Harrison Claydon.

Goals: Shala (16), Coker (90+1).