After scoring one goal in seven games the Mariners have now gone goal crazy with 10 in their last two outings.
Following their 6-0 rout at Boston last week they did it the hard way this time, giving Rovers a two-goal lead inside 20 minutes, before then turning the game on its head.
The score line looked close in the end, but a third Rovers goal with virtually the last kick of the match was immaterial.
Grimsby paid the price for some poor defending as first Craig Disley on 14 minutes and then Lewis Haldane on 20 minutes punished them to give Rovers what looked like a winning lead.
But the game's turning point was undoubtedly in the 27th minute when West Midlands referee Steve Bratt failed to award Grimsby a penalty after winger Peter Bore was unceremoniously tripped in the penalty area.
The injustice merely annoyed Grimsby and their biggest crowd of the season and they roared back to take a 4-2 lead by the 66th minute.
Danny North, in for the injured Martin Patterson, started the fight back on 33 minutes with his first senior goal.
Rovers still led at half time, but only for two minutes of the second half before skipper Justin Whittle headed a rare goal from a Tom Newey free kick.
Then, on 53 minutes, North played man-of-the-match Danny Boshell through and he finished superbly to put Grimsby in the driving seat at 3-2.
With Grimsby's shaky defence this was never going to be enough, so most of the crowd were able to breath easier after midfielder Ciaran Toner scored a fourth on 66 minutes.
This looked to have put the game beyond doubt, but Rovers created and wasted some good chances before defender Steve Elliott scored a consolation in added time.
For Rovers their defensive wheels have well and truly fallen off and they have now conceded eight goals in three games, while Grimsby, who had managed just one in seven, have now found their scoring boots with a vengeance.