Two early second-half goals sent the Mariners towards defeat as Milton Keynes Dons came from behind to win at Blundell Park.
Town dominated for long periods of the first half and held a deserved lead at the interval after Danny Rose opened the scoring.
But the visitors were level within four minutes of the restart through captain Alex Gilbey’s header, then Scott Hogan completed the turnaround to give the Dons the advantage.
The hosts aimed to get themselves back into the game but they were unable to find an equaliser and Connor Lemonheigh-Evans sealed the points for the away side as he grabbed a third goal deep into stoppage time.
George McEachran replaced Callum Ainley in the only change to David Artell’s Grimsby XI after the midweek away victory at Tranmere Rovers, while Jayden Luker came back into the matchday squad with a place on the bench.
Jackson Smith continued in goal, with Harvey Rodgers, Doug Tharme and Cameron McJannet forming a back three. Tyrell Warren and Denver Hume again operated as wing-backs as McEachran, Evan Khouri and Luca Barrington made up the midfield and Justin Obikwu was paired with Rose in attack.
Luker and Ainley were joined among the substitutes by Seb Auton, Lewis Cass, Jason Svanthorsson, Cameron Gardner and Donovan Wilson.
MK Dons sat three points and five places behind the Mariners in the Sky Bet League Two table at kick-off, although Scott Lindsey’s men had won both of their previous games and were looking to make it a hat-trick of victories.
Warren won the first corner of the game on the Town right but McJannet’s header from it was off-target, then goalkeeper Tom McGill caught a Rose cross as the hosts continued to show promising early signs.
Obikwu saw a strike blocked amid a handball appeal from the home fans, before McGill got down to deny Warren when the right wing-back sent a flick towards goal.
Town were on top in the early stages and Rose started another attack when he found Obikwu on the left but after cutting inside, the striker could not pick out a team-mate with his pull-back.
The away side’s first attack of note came on the quarter-hour when a good ball over the top found Joe Tomlinson, although his strike flew well over the bar.
Moments later, the deadlock was broken at the other end as the Mariners got the reward their early dominance had deserved. A free kick from midway inside the Dons half was played low into the box by Hume and ROSE stretched to beat Lemonheigh-Evans to the ball and steer it past McGill.
Rodgers was caught offside as McEachran sent another free kick towards the far post, before a through-ball from Tommy Leigh in the opposite direction proved too far ahead of striker Hogan.
Obikwu won a free kick near the corner flag on the right as Town created another opportunity to put pressure on the Dons’ goal and it led to a corner on the opposite flank after Hume’s delivery was touched behind by McGill. This time, the ball was headed through to the keeper.
Obikwu was then just wide of the far post with a low strike from the right after the Coventry City loanee got on the end of a ball from Rose and ran at centre-back Sam Shepping.
Leigh fired straight at Smith on 25 minutes after a patient build-up by the away side, then McEachran sent a lob attempt over the bar after a mistake by McGill.
The visitors were having more of the ball by the half-hour, although they had not created anything to trouble Smith in the Town goal and a free kick from the right flew harmlessly out of play.
Tomlinson was off-target with a shot from the edge of the box soon afterwards, before McJannet beat Hogan to a ball from Leigh to get it safely back to Smith.
Leigh sent a diving header over the bar as the away side continued to come forward with half-time looming, although they were unable to create any more opportunities and after one additional minute was played, the Mariners went in at the break with the lead.
SECOND HALF
No changes were made by either side before the restart and Town created the first chance of the second half two minutes in. McJannet burst down the left and played a brilliant ball over the top for Barrington to go clear, although his powerful strike from the edge of the box was blocked by McGill.
And soon afterwards, the hosts were punished for not taking the chance as the Dons found an equaliser. A patient build-up saw them work the ball from left to right and when Leigh’s cross picked out Gilbey, he had the simple task of heading past Smith from close range.
The momentum was now suddenly with the Dons and four minutes after levelling the scores, they completed the turnaround to take the lead. Aaron Nemane chased the ball down on the right and pulled it back across the six-yard line for Hogan to finish.
Town immediately looked to get themselves back on level terms and Obikwu headed over the bar at the far post from a free kick.
Luker was sent on for his Mariners league debut as he replaced Barrington three minutes before the hour, with Ainley coming on for McEachran at the same time as the hosts were the first to make changes.
McJannet cleared a long throw from Leigh, before Gilbey was shown the first yellow card of the game for a foul on Rose.
Obikwu was unable to work an opening for a shot when a Tharme long throw broke for him inside the penalty area, then an attempt by Khouri was blocked and McGill got down to stop the midfielder’s rebound.
Barrington fired wide from 20 yards as Town looked to be coming back into the game, before Kane Thompson-Sommer replaced Leigh and Ellis Harrison came on for Hogan as the Dons made changes to their attack on 73 minutes.
Lemonheigh-Evans won a corner for the away side two minutes later but after it was played short and worked into the box through Liam Kelly, the danger was cleared.
Wilson replaced Obikwu in Town’s latest substitution, with MJ Williams coming on for Kelly in the red of MK Dons soon afterwards.
Another Tharme long throw caused problems until Lemonheigh-Evans eventually got the ball away, before a foul on Rose gave Town an opportunity to create more danger with a free kick midway inside the Dons’ half. Hume played it short to Ainley and after a scramble, his chip into the box was eventually dealt with.
Warren was booked for a foul with two minutes to go, then Gardner and Svanthorsson were sent on in place of Rose and Rodgers as Town aimed to snatch a point.
The Mariners were given at least seven additional minutes to find a late equaliser, although a Hume free kick from the right was cleared.
Hume was booked for bringing Nemane down after the winger broke down the left, then Harrison became the latest to see the yellow card for holding onto the ball and delaying a Town throw-in when a free kick was not given his way.
But with two of the extra minutes still to play, the visitors made sure of the three points when they grabbed a third goal. Harrison held off Tharme and played the ball to Lemonheigh-Evans, who arrowed a low strike past Smith and into the net to make it 3-1.
Town are next in action on Tuesday, when Manchester City U21 will be the visitors to Blundell Park for a Bristol Street Motors Trophy group stage match.
Town: Smith, Rodgers (Svanthorsson, 88), Tharme, McJannet, Warren, McEachran (Ainley, 57), Khouri, Barrington (Luker, 57), Hume, Rose (Gardner, 88), Obikwu (Wilson, 76)
Subs not used: Auton, Cass
Attendance, brought to you by Elegant Beds: 5,853
