The hapless Mariners were outplayed, finishing with nine men and the Quakers could even afford a missed penalty before sub Guylain Ndumbu-Nsungu gained the points 11 minutes from time.
The penalty, correctly awarded by Hull referee Carl Boison came after tremendous skill from 19-year-old Anthony Peacock in his first full start for the club.
Wasteful Darlington squandered an earlier opportunity when striker Clyde Wijnhard saw his 64th minute penalty blocked by Grimsby keeper Steve Mildenhall, who looked embarrassed to accept the sponsors man of the match award. But the giant keeper should not have done as a string of fine saves kept his side in the game.
Grimsby went down to 10 men on 79 minutes when wing back Tom Newey was sent off for conceding the first penalty, and then right at the death central defender Tony Crane talked himself into an early bath for offensive and abusive language.
In both games last season Darlington were outplayed by Grimsby and on the admission of the Darlington manager were lucky to pick up the six points.
But there was no disputing Darlington's supremacy this time and their passing style of play was too much for a disappointing Grimsby who carried too much threat for a more direct Grimsby.
But it would have been a different game if Darlington keeper Sam Russell had not made a brilliant double stop to deny Grimsby striker Michael Reddy who was clear on goal.
Blundell Park was not a happy place for the home supporters, but the 300 travelling fans went home far happier than they did last season even thought the result was the same.