Jack Moylan's dramatic late winner earned City all three points in the Lincolnshire Derby at Grimsby Town.
The Imps had to come from behind after Jason Svanthorsson scrambled home to put the hosts ahead, but Bailey Cadamarteri's goal drew City level before Moylan's strike four minutes into time added on moved his side up to second in Northern Group G.
Ethan Hamilton was handed his first start of the season after recovering from injury as City head coach Michael Skubala made a number of changes.
The home side fashioned the first opening as Justin Obiku headed wide after five minutes, but after that it was the Imps who had the early opportunities.
Crosses from Tom Hamer and Saxon Earley were warning signs for the hosts and, after 15 minutes, Hamilton forced the first save of the match as Jackson Smith got down to hold his low free-kick effort.
Cadamarteri threatened to get on a right-wing cross from Erik Ring, and moments later saw a shot blocked before he sent the rebound wide.
Hamilton saw another shot blocked after 25 minutes when he collected the ball off Moylan, with the midfielder then going close with the rebound.
The home side fashioned their best chance of the opening half shortly after with a dangerous right-wing delivery from Jayden Luker - Cameron Garder did really well to stretch and get a foot on the cross, but he was stretching just too much to keep his shot down.
City almost scored from the very next attack as home keeper Smith dropped the ball under pressure from Earley - it fell to Cadamarteri who saw his effort come crashing back off the left-hand post.
Both sides were looking to attack and George Wickens had to be alert to keep out Lurker's curling effort, with Obikwu's follow-up shot ending up in the stands.
There was a hairy moment for the home side after 51 minutes when a short goal kick from a defender left Smith exposed - Cadamarteri closed him down to block his attempted clearance. The ball could have bounced anywhere but - to the relief of Smith - it ended up wide of his goal.
The home side took the lead after 58 minutes when Wickens could not hold a long-range effort, and Svanthorsson - one of three half-time changes made by Mariners manager David Artell - scrambled the ball home before Wickens could readjust to intercept.
With the game hitting the hour mark, Skubala made two changes - with Reeco Hackett, making his first appearance of the season after recovering from a shoulder injury, and Dom Jefferies coming on.
City drew level after 66 minutes. Moylan sent in a deep inviting cross from the left and Cadamarteri rose highest to head home.
Momentum was back with the Imps, and they enjoyed plenty of possession albeit without carving out clear-cut chances to take the lead.
Moylan fired over, as the home side backed off and allowed him space to tee up a shot from just outside the area.
Cadamarteri was close to getting on the end of a Hackett cross with five minutes to go and did have the ball in the back of the net in the first minute of time added on - only for referee Oliver Mackey to rule it out after judging Draper to have fouled keeper Smith.
It looked like the tie was going to finish level, but Moylan's late moment of magic saw him create space for himself on the edge of the area before firing home a late winner into the bottom right corner.
Imps: George Wickens, Erik Ring, Lewis Montsma, Adam Jackson (c) (MJ Kamson-Kamara, 71), Tom Hamer, Saxon Earley (Reeco Hackett, 59), Oisin Gallagher (Ethan Erhahon, 83), Jack Moylan, Ethan Hamilton (Dom Jefferies, 59), Rob Street (Freddie Draper, 71), Bailey Cadamarteri. Subs not used: Jamie Pardington, Denny Oliver.
Grimsby Town: Jackson Smith, Matty Carson, Harvey Rodgers, Jayden Luker (Jason Swanthorsson, 46), Justin Obikwu (Rekeil Pyke, 46), Luca Barrington (Lewis Cass, 63) Callum Ainley, Tyrell Warren, Cameron Gardner, Doug Tharme, Evan Khouri (c) (George McEachran, 46). Subs not used: Seb Auton, Henry Brown, Denver Hume.
Referee: Oliver Mackey.
Attendance: 1,270 (475 away).
