Chester barely had to move out of second gear as they climbed to tenth in the table with a play-off place firmly in sight.
Chester dominated throughout and easily avenged an earlier 2-0 home defeat this season at the hands of the Mariners.
Grimsby managed to keep the scoresheet blank in the first half mainly through keeper Phil Barnes who saved brilliantly from David Artell and Jon Walters.
But the keeper could do nothing when Chester broke through on 53 minutes.
A Roberto Martinez corner was headed against the bar by Ashley Westwood and Artell bravely dived in to head home the rebound injuring himself in the process.
With Grimsby not having a shot on goal all night that would have been enough, but Gregg Blundell headed home a deep cross on 71 minutes to make absolutely certain of the points.
Grimsby made a double switch on 67 minutes bringing on striker Danny North and midfielder Gary Harkins but it made little difference.
The home side had a bit more of the play in the closing stages and full-back Tom Newey went on a splendid run only to be denied by a great block by the impressive Artell.
But it was unbelievably easy for Chester who might have had next week's replay in the FA Cup with Ipswich on their minds, but they clearly fancy their chances of making the play-offs.
Right from the start the visitors knocked the ball about impressively and dominated the match as if they were the home side.
Apart from a shot from full-back John McDermott which whistled just wide, the home side could offer nothing in way of a threat at goal and the home fans grew more disgusted in the pouring rain.
Grimsby are going through a terrible spell at the moment and it doesn't promise to get any easier with their next match being a visit to leaders Walsall who have only lost twice all season.
Strangely the first of those was against Grimsby who beat them 2-1 at Blundell Park, but a repeat seems highly unlikely the way the Mariners are playing at the moment.