There were just two changes to City’s starting XI in Cleethorpes as goalkeeper Viktor Johansson and defender Calvin Ughelumba returned, replacing Eldin Jakupović and Luke Thomas respectively.
Last time out, in Premier League 2 Division 1 on Friday, the Foxes enjoyed a 3-0 success over Southampton at a rain-lashed Holmes Park and the prospect of facing Sky Bet League 2 opposition would have been another exciting challenge for the visitors.
Deploying a fluid 4-2-3-1 formation in the early stages, Leicester were authoritative in possession and unfazed by their more experienced opponents in chilly conditions.
The first moment of concern for City came on 16 minutes as Liam Gibson crossed deep for Harry Cardwell, who took a touch and hit it low, but Johansson was there to save calmly.
Shortly after, Callum Wright and George Thomas linked up before the former searched for Khanya Leshabela at the far post, only being denied by a late intervention from Harry Davies.
It was an opportunity which came as City were starting to find some momentum and they could have been ahead on 20 minutes as Admiral Muskwe’s effort was later disallowed for offside. The Mariners, though, took the lead just after the half-hour mark.
When Moses Ogbu leapt highest, there was little City’s backline, nor Johansson, could do to prevent the 28-year-old, who has previously played in Sweden and Saudi Arabia, from heading in at the far post.
After the interval, Belgian forward Eppiah, who scored against the Saints last Friday, replaced Leshabela for City, but it was the home side who initially showed the most urgency.
With 55 minutes gone, goalscorer Ogbu looked to turn provider when his cross found Ahkeem Rose in the 18-yard box, but the Jamaican’s low header was scooped up by Johansson.
Muskwe, on the other hand, was unfortunate again on the hour as Kiernan Dewsbury-Hall’s excellent cross found him in space. However, Grimsby stopper Sam Russell was aware to his drive from distance.
As the clock ticked down, City’s youngsters posed a far greater threat and could have levelled through either Filip Benković or Darnell Johnson, who both had efforts blocked by a crowd in the area.
However, their moment did come with 17 minutes to play as the industrious George Hirst burst into a pocket of space and galloped at goal, taking two defenders with him on the left flank.
His deft lay-off for Eppiah was perfect and the 21-year-old did the rest, stylishly powering it beyond Russell, into the bottom corner, to make it 1-1 late on at Blundell Park.
It was so nearly 2-1 to Leicester on 77 minutes, meanwhile, as Thomas’ free-kick bounced up for Hirst to nod it towards goal, only to be excellently palmed away by Russell in the hosts’ net.
Just as the fourth official's board rose to the heavens, the home crowd were on their feet, applauding their opposition - as an extraordinary strike by Eppiah, from 25 yards, settled the encounter.
Major moment
Just as both sides began to contemplate a penalty shootout, Josh Eppiah showed everyone at Blundell Park why he is so highly regarded by coaches within the Club's Academy.
He seized the ball under his control, took a moment to gather his thoughts, and arrowed it straight into the top corner, securing his third goal in two matches, and winning all three points.
Who impressed?
Half-time substitute Josh Eppiah immediately injected energy into Leicester’s attacking phases with his direct style causing havoc among Grimsby’s backline.
Eppiah's 67th-minute strike – his second in as many games after a lengthy injury lay-off – was a fitting reward for his efforts. His second, on the other, was simply a touch of brilliance.
Where does it leave us?
Leicester leap up into first place in Northern Group A with five points from two games, after last month sealing a bonus point for winning a shootout following a 1-1 draw at Scunthorpe United.
The Iron are in fact sat in second place on four points, Sunderland are in third, on three, while Grimsby are bottom of the standings with zero after playing all three of their fixtures.
Next up…
It’s a three-day turnaround for City’s youngsters, who travel to Manchester City in Premier League 2 Division 1 on Friday (7pm GMT kick-off) – a fixture you can watch live and for free on LCFC TV.
The details…
City: Johansson; Clark, Benković, Johnson, Ughelumba; G. Thomas (c), Dewsbury-Hall; Wright, Muskwe (Arlott-John 86'), Leshabela (Eppiah 45’); Hirst
Subs not used: Stolarczyk, O’Connor, L. Thomas, Leathers, Tee
Goal: Eppiah 67’, 90'
Attendance: 341