Contrasting fortunes for the game's two top strikers combined to ensure that Aldershot Town became the first team to reel in the Mariners this season in an entertaining encounter at the Electrical Services Stadium.
Visiting front man Lenell John-Lewis played his part as the pantomime villain after getting himself sent off for picking up two bookings in a mad five-minute spell towards the end of the first half.
And unbeaten Grimsby were made to pay as two goals from opposite number Brett Williams after the break handed Aldershot a third win of the season, and undoubtedly their best yet.
John-Lewis, already yellow carded for a rash lunge on Sam Hatton, then saw red on 35 minutes after pulling back the counter-attacking Dan Fitchett right in front of referee Rob Whitton.
And after boss Andy Scott made a double substitution at half-time in a bid to seize the advantage, the Shots got their just reward with Williams' double taking his tally for the season to five before Scott Neilson set up a tense finale with a goal back 13 minutes from time.
“The sending off is a major factor and we said to the lads at half-time that we are going to take the game to them and try to win it, a delighted Scott said afterwards. “The second-half performance for half an hour was brilliant.
“It was a good game to watch because they kept on going and it was entertaining.”
Grimsby scored 13 goals in the space of 48 hours last weekend and up until John-Lewis' sending-off, they looked in the mood for more.
Both Craig Clay and John-Lewis brought out the best in Shots keeper Phil Smith before Paddy McLaughlin's inswinging free-kick from the right sped through a crowded penalty area before cannonin off the far post.
Shots captain Glenn Wilson then blocked blocked Jon-Paul Pittman's shot from a tight angle.
But despite enjoying plenty of possession football in the Grimsby half, Aldershot didn't look like opening the door and Scott's responded by introducing Anthony Tonkin and Joe N'Guessan at the back, for the ineffective Mark Molesley and Hatton.
And with their first serious assault on the Grimsby goal, Aldershot took the lead. Jordan Roberts, now playing on the left flank threaded a lovely ball through to Fitchett, who squared the ball back from the by-line for the marauding Williams to slam home his fourth goal of the season.
Williams almost put the Shots in dreamland two minutes later when forcing James McKeown into a spectacular diving save with a shot on the turn eight yards out.
But it only delayed the inevitable as the resurgent Shots added a second on 64 minutes. Fitchett hooked a hopeful ball forward, Williams nipped in front of a dithering Shaun Pearson and in full stride, rolled the ball under the advancing McKeown.
Just when the Shots looked to be coasting, Tonkin's miscued clearance fell straight to the feet of Neilson, who volleyed home a quite brilliant effort from 25 yards to halve the deficit but the Shots weren't to be denied.
Shots: Smith; Gibbs, Wilson, Oastler, Roberts; Hatton (N'Guessan 46), Lathrope, Forbes, Molesley (Tonkin 46); Williams, Fitchett (Derry 76). Subs: Thomas, Plummer.
Ref: Rob Whitton. Att: 1,998 (344).