The Mariners fell to defeat as two second-half goals earned Crewe Alexandra all three points at Blundell Park.
In an evenly-matched contest between teams who both sat in the Sky Bet League Two play-off places at kick-off, two moments of quality from the visitors proved to be the difference.
Both sides had created opportunities in a goalless first half but Crewe took the lead through a lob from Jack Lankester 10 minutes after the break.
And the striker then turned provider seven minutes later when he set midfielder Joel Tabiner up to make it 2-0.
Town refused to give up but despite another positive performance, they were unable to find a way back into the contest.
Two changes were made to the Grimsby team after last week’s away victory over Morecambe, with Doug Tharme replacing the suspended Harvey Rodgers and Jordan Davies coming in for George McEachran, who moved to the bench.
Jordan Wright started in goal, as Lewis Cass, Tharme, Cameron McJannet and Denver Hume formed the defence. Davies joined Kieran Green and Curtis Thompson in midfield, while Jayden Luker and Jason Svanthorsson lined up either side of striker Justin Obikwu.
McEachran was joined among the substitutes by Seb Auton, Luca Barrington, Rekeil Pyke, Callum Ainley, Evan Khouri and Danny Rose.
Crewe began the day level on points with the Mariners in the league table, although the Railwaymen had a better goal difference record going into the game.
They were without top scorer Shilow Tracey through suspension, so Lankester and Matus Holicek would instead aim to provide the main goal threat. Former Town fans’ favourite Omar Bogle was among the subs for the Cheshire side.
Two early Mickey Demetriou long throws were well-defended by the hosts, before Luker and Obikwu linked up as Town went forward for the first time.
Wright’s first action came on four minutes when he tipped a Lankester strike from a narrow angle over the bar for a corner, before Lankester turned a Ryan Cooney cross wide at the near post as the visitors enjoyed the better of the early exchanges.
A foul on Svanthorsson gave the Mariners a free kick inside the Crewe half and it led to their first good chance as Hume picked Tharme out at the far post but the centre-back’s header flew over the bar.
Crewe responded with a quick break down their left but good defending by McJannet saw him get to Max Conway’s cross ahead of Holicek.
Luker beat Demetriou to get on the end of a long ball on 19 minutes, although he was unable to create a shooting opportunity as Max Sanders got back.
A corner at the other end looked to have caused problems as the delivery from the left was missed by Wright but nobody could take advantage at the far post.
The Town keeper then produced a brilliant save from a snap-shot by Lankester as the Crewe pressure continued, before a cross from Hume at the other end flew over the bar for a goal kick following good play by McJannet and Svanthorsson on the left.
Obikwu needed treatment when he went down just before the half-hour but was passed fit to play on, then another stoppage came for Svanthorsson to have treatment before he also rejoined the action.
Hume saw a strike blocked from distance as the home side began to have more of the ball in attacking areas, before Obikwu went down again on 39 minutes and this time, was unable to continue. Rose was sent on in his place.
Rose’s first action saw him win a throw-in on the left and Tharme’s long throw was headed back to him but the defender’s follow-up cross sailed out of play at the far post.
A foul on Cass brought a free kick on the right but Hume’s delivery was caught by Crewe goalkeeper Filip Marschall.
Four added minutes were played at the end of the first half and with no further opportunities coming for either side, the game remained goalless at the break.
SECOND HALF
No further changes were made by either side before the restart and the Mariners began positively, winning an early corner on the right. Hume’s ball from it was headed clear.
Thompson saw the first yellow card of the afternoon for a trip on Lankester, before Tharme did well to win a goal kick at the other end in a challenge with Sanders.
A foul on Green gave the hosts a free kick on the right and Hume’s delivery broke for Svanthorsson but his low shot was blocked.
Tabiner almost took advantage of a mistake at the other end but saw his shot blocked by McJannet, before Sanders fired just wide from 20 yards.
The next time they went forward though, the visitors took the led. A perfectly-flighted ball over the top from Sanders fell into the path of Lankester, who kept his composure to lift it over the advancing Wright.
Town’s initial response to going behind was good and great play by Luker saw him win the ball from Conway and set up an attack which led to a free kick when Davies was brought down by Demetriou, who was booked.
But soon afterwards, the home side’s task was made tougher when Crewe doubled their advantage. A quick break saw Tabiner take the ball forward into the Town half and find Lankester on the left. He looked up and played a return pass for Tabiner, who steered a low shot past Wright from 12 yards.
McEachran and Khouri replaced Davies and Thompson as Town made a double substitution soon after the goal, while Bogle and Owen Lunt came on for Lankester and Holicek in the sky blue of Crewe.
James Connolly was booked for an off-the-ball push on McEachran as Crewe lined up for a corner and the flag-kick then led to a penalty appeal when Bogle went down but the referee waved play on.
Zac Williams became the latest Crewe player to see the yellow card for delaying a throw-in, before Rose had an opportunity from the edge of the box but saw his shot blocked for a corner.
Town boss David Artell made his final substitutions with 10 minutes to go, as Barrington and Pyke replaced Svanthorsson and Luker.
A Hume corner was cleared soon afterwards, before Barrington and Pyke both had shots blocked as the Mariners looked for a way back into the contest.
Jack Powell and Fin Roberts replaced Sanders and Tabiner for the visitors on 83 minutes, before Cass won a corner but when it fell for Tharme, his shot was straight at keeper Marschall.
Charlie Finney then came on for Conway in the last substitution of the game with three minutes remaining.
A minimum of seven added minutes gave Town further opportunity to get themselves back into the game but when Hume sent a free kick wide from 25 yards, it proved to be their last chance as Crewe saw out what was left on the clock to collect the points.
The Mariners are next in action on Saturday, when they travel to Swindon Town.
Town: Wright, Cass, Tharme, McJannet, Hume, Green, Thompson (McEachran, 67), Davies (Khouri, 67), Luker (Pyke, 80), Obikwu (Rose, 39), Svanthorsson (Barrington, 80)
Attendance, brought to you by Elegant Beds: 5,745