The goal was totally out of keeping with what had gone before for on a bitterly cold night.
It was an awful game that had a goalless draw written all over it from the kick off.
But with nine minutes left, Grimbsy substitute Thomas Pinault sparked a quick break from midfield and, when a cross came over from the right, striker Martin Gritton gleefully knocked in his third goal of the season.
There seemed little likelihood of Chester hitting back for they had been as shot-shy as the Mariners.
But in the final minute there was a scramble in the Grimsby six-yard box and goalkeeper Anthony Williams - after being almost totally unemployed - had to react quickly to knock the ball away as it flashed across the goal.
Such was the game that Grimsby did not win their one and only corner until two minutes from time and not surprisingly it produced nothing.
Exciting moments were few and far between and the weather conditions were the main talking point.
That said it was an important three points for Grimsby and their second successive clean sheet following the excellent goalless draw against Swansea on Saturday.
It will surely be a different story when league leaders Yeovil make their first visit to Blundell Park on Saturday.
For Chester boss Ian Rush there is still some work to do if his side are to pull away from an immediate return to the Conference, but on the evidence of this performance they should have enough to stay in the Football League.