The Mariners dominated the contest at the Mornflake Stadium and got a deserved reward of all three points.

Toby Mullarkey opened the scoring on 38 minutes and a Curtis Thompson volley just before the hour made the points safe.

Substitute Denver Hume then added a late third goal to cap an excellent team performance and seal only a second away win of the campaign.

And with results elsewhere going in the Town’s favour, they now require just one more point from their remaining three games to be certain of retaining their EFL status.

Grimsby boss David Artell made two changes to his team for the trip to face his former club, with Kieran Green and Charles Vernam replacing Jamie Andrews and Harry Clifton from the XI that began the midweek defeat at Harrogate Town.

Jake Eastwood continued in goal, with Mullarkey, Doug Tharme and Harvey Rodgers forming the back three as Liam Smith and Vernam operated in the wing-back positions.  Gavan Holohan, Thompson and Green were the midfielders, while Danny Rose and Justin Obikwu led the attack.

Andrews and Clifton were both named on the bench, where they were joined by Seb Auton, Callum Ainley, Abo Eisa, Hume and Donovan Wilson.

Crewe began the day fifth in the league table and aiming to move to within three points of the automatic promotion zone with a win, if other results were to go their way.  Lee Bell’s side knew, however, that a victory would be likely to guarantee at least a play-off place.

Aaron Rowe sent a deflected strike through to Eastwood from 25 yards as the home side registered the first attempt at goal.

Obikwu was then inches away from giving the Mariners the lead after Green found him on the edge of the penalty area.  The Coventry City loanee worked an opening for a shot but a deflection on his low effort took it just past the post for a corner, which was cleared.

Rose won a free kick on the right on eight minutes, although Vernam’s delivery into the box was headed away from goal.

Green almost took advantage of a loose ball in the Crewe penalty area three minutes later but the midfielder’s touch took it through to Max Stryjek, making his debut in the home goal after joining on an emergency seven-day loan from Wycombe Wanderers.

A half-volley from Elliott Nevitt was blocked for a corner at the other end and the delivery from the flag was volleyed away for a throw-in by Rose.  Mickey Demetriou’s long throw was half-cleared but the return ball into the box was held by Eastwood.

Obikwu won a Town corner after a strong run by Rodgers but Vernam’s flag-kick was dealt with as Charlie Kirk brought the ball clear.

Another away corner followed when a long ball was headed behind by Zac Williams, although again, it did not lead to a chance in front of goal.

Rose needed treatment after staying down following a challenge with Ryan Cooney.  He was initially passed fit to continue but went down again soon afterwards and was replaced by Wilson as Town made the first substitution on 21 minutes.

Tharme’s first opportunitty to use his long throw came soon afterwards and it led to a blocked shot from Vernam, before Eastwood got down to stop a 20-yard strike by Nevitt at the other end.

A foul on Obikwu brought a free kick midway inside the Crewe half but Vernam’s chip into the box was headed clear, then Stryjek made a comfortable stop from Wilson after good play by Green.

A good challenge by Rodgers inside his own penalty area stopped Nevitt and got the ball away for a corner after the striker had been picked out by Demetriou.  Rodgers then flicked the flag-kick clear.

Another home corner came when a shot from Rowe was deflected over the bar, although Mullarkey was first to the ball from the flag and Vernam completed the clearance.

Cooney became the first of the afternoon to see the referee’s yellow card when he brought Vernam down on the Town left.  Vernam took the free kick himself but his cross-shot bounced off the top of the bar for a goal kick.

The Mariners’ next attack led to the opening goal on 38 minutes, as a long throw from Tharme on the left was met by MULLARKEY and his header beat Stryjek.

A Demetriou long throw at the other end was cleared as Crewe looked to respond to falling behind, before a Green cross from deep on the left proved to be too far ahead of the run of Holohan at the far post.

Mullarkey was booked for a late challenge on Rio Adebisi and Kirk was also shown the yellow card at the same time.

No further chances came before the half-time whistle, so the Mariners went into the dressing rooms at the interval with the lead.

No further changes were made before the restart and an early shot by Rodgers was blocked for a corner after Obikwu flicked the ball through for the defender.

Another corner followed on 50 minutes as Town’s positive opening to the second half continued, although Vernam’s ball from the right was cleared after it had been headed on.

A Tharme header was blocked from the visitors’ third corner of the half and a handball appeal against Rowe was then turned down by the referee.

The Mariners were pushing for a second goal and Crewe responded with a double-substitution, as Joel Tabiner replaced Josh Austerfield and Charlie Finney came on for Kirk.

A Holohan cross was blocked for a further corner on 59 minutes and this time, Town made it count as Vernam’s delivery was headed as far as THOMPSON and he hit a neat volley past Stryjek from 16 yards to make it 2-0.

Lucas Sant replaced Rowe in Crewe’s third change, before Williams was booked for bringing Vernam down on the Grimsby left.  Vernam’s free kick was headed over the bar by Green.

A foul on Green brought another free kick inside the home half and after the ball was initially worked down the right, Rodgers did well to chase it down and win a corner on the left.

Town were continuing to dominate and another corner came when a Tharme long throw was headed behind by Nevitt.  Tharme saw a header blocked from Vernam’s delivery and Stryjek then made a good save to deny Obikwu from a narrow angle.

The game was being played inside the Crewe half and good work by Holohan saw him earn a free kick on 69 minutes, which led to the 12th Town corner of the afternoon when Tharme’s header was deflected behind.

Wilson sent a shot over the bar after a run and pull-back from Green on the right, before a rare Crewe attack came to nothing as a low cross was cleared by Rodgers.

Stryjek raced off his line to beat Wilson to a long ball, then a stoppage came for Eastwood to receive treatment after the goalkeeper went down, although he was passed fit to play on.

Clifton and Hume replaced Green and Vernam with eight minutes to go, then Eastwood had to scramble back and clear off his line after a mistake almost saw Nevitt halve the home side’s deficit.

That proved to be the start of a brief spell of Crewe pressure and a corner  from the right was cleared, before a brilliant double-save from Eastwood kept out Finney’s far-post volley and the rebound, which ricocheted back off Tharme.

Ainley replaced Obikwu on 88 minutes and Andrews came on for Holohan as the Mariners looked to their bench again.

And Town were not yet finished with the goalscoring, as they added a third just before the game moved into six added minutes.  Wilson made his way into the box on the right and pulled the ball back for HUME to apply an assured finish.

The Mariners closed out the remainder of the contest to collect a huge three points and move six points clear of the relegation zone, with a favourable goal difference.

And with 23rd-placed Sutton United only having two games left to play, Town will travel to Colchester United on Tuesday knowing a draw or better would ensure League Two safety.