Two Grimsby goals in as many minutes straight after the interval sent Sheffield Wednesday crashing to a 2-0 defeat and left beleaguered boss Chris Turner still grappling for a first win.
It was rough justice on rock-bottom Wednesday who dominated the opening 45 minutes, but until Turner can find a proven goalscorer chance after chance will always go begging.
After coming off second best at half-time, the Mariners stormed into a two-goal lead within seven minutes of the restart, George Santos powering home the first with his head and Darren Mansaram breaking Wednesday hearts with a deflected second three minutes later.
With confidence in such short supply the visitors were never going to recover, but if they had converted just one of their first-half chances this could have been a different story.
Turner made just two changes from the side that went down to Gillingham at Hillsborough last week.
Irishman Derek Geary returned from suspension to fill in for David Burrows (torn hamstring) at left-back, while Steve Haslam stepped in at right-back for Ryan Green, who took a knock in training on Friday.
The Mariners were without Tony Gallimore and John McDermott, while player-boss Paul Groves took his place on the bench.
In only the second minute Wednesday`s Gerald Sibon headed wide from on-loan Allan Johnston`s pin-point cross, while Wednesday skipper Trond Soltvedt did well to block Alan Pouton`s goalbound shot from 25 yards.
Wilting Wednesday - they have won only two matches in Division One this season - started full of purpose, but honours were even in the opening 15 minutes, Grimsby striker Mansaram seeing his drilled, left-footed shot held by Wednesday keeper Kevin Pressman.
Mariners striker Steve Livingston was booked for his full-blooded challenge on opposite number Shefki Kuqi, who then squandered a gilt-edged chance when glancing Matt Hamshaw`s cross wide from six yards.
Sibon then stung Town keeper Danny Coyne`s hands from 20 yards and Johnston whipped in a series of telling crosses as Wednesday began to unnerve the home side.
Pouton let fly again with another long-range effort that fizzed wide, but it was Turner`s side who looked the more likely to break through.
Wednesday pumped balls into Grimsby`s penalty area from all angles and Johnston`s effort from the edge of the box was blocked by Darren Barnard, while Sibon failed to trouble Coyne with another close-range header.
Grimsby had only a weak header from Stacy Coldicott during a prolonged period of Wednesday pressure.
Paul McLaren flashed one wide from 30 yards, Kuqi fired in a well-struck volley that flew over the bar and Matt Hamshaw went close with another long-range shot.
But just four minutes after the break Wednesday`s first-half dominance counted for nothing. Pouton swung in a corner to the far post and Santos rose to power home his header in off the post.
And all of a sudden Grimsby were two goals to the good. John Oster broke clear down the left and his pull back was converted, via a deflection, by Mansaram to turn the game on its head.
Almost immediately Wednesday`s troubles were highlighted, Sibon and Kuqi squandering close-range headers with frustrated boss Turner forced to pitch on-loan Wolves striker Adam Proudlock into the fray for Kuqi.
Geary joined McLaren in referee Mike Halsey`s notebook for rash tackles as the stunned visitors lost their shape and Grimsby almost grabbed a third via another Oster-Santos one-two, the latter hitting the woodwork from a searching cross.
Tony Crane blocked another Santos header from Barnard`s cross before Sibon skewed a close-range effort from Geary`s cross wide and Turner threw on striker Leon Knight for Hamshaw in a brave but ultimately fruitless bid to rescue something from the game.