In the process they overwhelmed basement county neighbours Boston with a free-flowing show of attacking football, highlighted by a Peter Bore hat-trick.
And after netting only once in their previous seven games, the Mariners profited fully on a day when Boston capitulated totally and dropped further down the table.
Early drama arrived in only the fourth minute when the Visitors went ahead.
Bore dispossessed a dithering Shane Nicholson and fed Martin Paterson whose shot was blocked by Andy Marriott. The ball broke for Ciaran Toner to chip back into the area where Bore headed in unchallenged from five yards.
Three minutes later, further weak defending down the left by Boston gave Bore the chance to cross. Marriott could only tip the ball upwards and James Hunt side-footed in at the far post.
Boston hit back and went close in the 13th minute when debutant Nathan Joynes chipped over keeper Phil Barnes but Nick Fenton got back to clear off the line.
The 20th minute brought Grimsby even more rewards with Toner swivelling on a loose ball before driving a fierce 25-yarder past Marriott.
Boston were shell-shocked but went close to a 26-minute reply when Justin Whittle cleared off the line from a Francis Green header.
The home side were again out of luck on 34 minutes when Joynes crossed from the right and Drewe Broughton's header crashed away off the bar.
In the 42nd minute Grimsby netted their fourth when Tom Newey charged down the left and crossed for Bore to head in unmarked from close range.
Grimsby struck another telling blow in the 61st minute. From Newey's corner, the Mariners first of the game, Fenton rose to head against the bar and Paterson reacted quickly to hook the loose ball over the line.
The home side lacked any pattern or cohesion to their play and mustered only token threats on the visitors' goal with Paul Ellender seeing a weak header held by Barnes and substitute Ernie Cooksey shooting tamely wide.
Grimsby netted their sixth goal 12 minutes from time, with Bore completing his hat-trick drilling in at the near post to convert a low cross by Paterson.