With the goal coming just before half-time Chesterfield swelled their defensive ranks throughout the second-half and were content to hit the home side on the break.
But for Grimsby their poor set-pieces and their over-reliance on high balls played into Chesterfield's box made it too easy for the visitors.
The Spireites' defence was expertly marshalled by experienced skipper Robert Page and on-loan keeper Trevor Carson did not have a serious shot to save.
Then again neither did Grimsby's Phil Barnes who had no chance with Jamie Ward's matchwinner.
It followed a Grimsby set-piece upfield and a mistake by Nick Hegarty let in Darren Currie who fed Ward for a simple finish.
Earlier Ward had missed an even easier chance, allowing Barnes to make the save.
The early kick-off and the heat certainly cooled the enthusiasm of the players and crowd alike and it was a poor spectacle.
It left Grimsby chasing their first league goal of the season, while Chesterfield made it two wins out of two on their travels.
Next up for Grimsby is a difficult looking Carling Cup tie at Blackburn Rovers and then comes a Lincolnshire derby at Lincoln City, before a re-match with Chesterfield in the Johnstone's Paint Trophy.
Last season the Mariners made it all the way to Wembley before losing 2-0 against the MK Dons. They really need to stabilise their league form without getting embroiled in any of their three cup campaigns.
Chesterfield meanwhile made light of the loss of top scorer Jack Lester, who is likely to return at Saltergate when the sides clash again shortly.