Grimsby virtually secured their Football League survival with an emphatic 3-0 win at play-off hopefuls Crewe thanks to goals from Toby Mullarkey, Curtis Thompson and Denver Hume.

The Mariners are six points clear of second-bottom Sutton, who only have two games to play, but hold a far superior goal difference than United.

Justin Obikwu wasted an early opening for the visitors when he was put clear in the box, but he took too much sizing up goal and Lewis Billington’s intervention steered the striker’s effort past the post.

Crewe goalkeeper Max Stryjek was at fault when Doug Tharme’s long-throw was headed on by Mullarkey with the keeper pushing the ball weakly into the air and then unable to prevent it creeping over the line in the 38th minute.

And the visitors doubled their lead from another set play just before the hour mark with Thompson volleying home Charles Vernam’s outswinging corner from the edge of the box.

Crewe’s response was tame, although Jake Eastwood needed to take evasive action to prevent Nevitt’s block on his clearance from crossing the line and then the Grimsby keeper did well to keep out an effort from Charlie Finney in the closing minutes.

But substitute Hume rounded off the Mariners’ afternoon when he finished off into the far corner after Donovan Wilson cut the ball across the box.