Charlton moved into the third round of the Carling Cup but it was hardly an inspiring performance.
The Premiership outfit survived something of a battering but scored early on and then late in the game to clinch their first away win of the season.
In between, Grimsby ran the show and were desperately unlucky not to have something to show for it.
The first goal after eight minutes could have stunned Grimsby but it had exactly the opposite effect.
A free-kick from the edge of the box by Danny Murphy was struck perfectly and Charlton looked to be up and running in a competition in which they have a poor record.
But Grimsby roared back like a wounded tiger and in a terrific spell they put Charlton under immense pressure.
Michael Reddy fired wide, Ashley Sestanovich almost broke the bar after a fantastic run and strike, while Andy Parkinson forced a good parry from Charlton skipper and keeper Dean Kiely.
Charlton were happy to reach the dressing room at half time with their lead still intact.
The second half was much the same but Grimsby could not get the equaliser they certainly deserved.
Then with men committed forward Grimsby fell to the sucker punch when substitute Kevin Lisbie fed striker Francis Jeffers and he showed England class to beat Anthony Williams with an angled shot.
The result was rough justice on the Mariners who deserved so much more.