Wrexham suffered defeat for the first time under Phil Parkinson, as three well-taken goals, including one from ex-Red Dragon Luke Waterfall, earned The Mariners all three points.
Parkinson made two changes from the side which beat Woking on Saturday: Max Cleworth returned to the back three in place of Harry Lennon, and Jordan Davies failed to recover from the injury he picked up on Saturday and was replaced by Devonte Redmond. On the bench, Shaun Brisley was included in a first team squad for the first time, with Cameron Green returning to the 16.
The match got off to an even start, with the first spell of sustained pressure from either side ending after 10 minutes with a Hunt free kick which was headed powerfully wide by Waterfall from 10 yards.
Soon afterwards Wrexham had a fright when Rob Lainton came into a crowd to punch clear from another Hunt free kick, but landed awkwardly on his neck. Fortunately, after a lengthy spell of treatment he was able to continue.
In the 23rd minute Wrexham took the lead. A massive tackle on the half way line by Aaron Hayden allowed Luke Young to send Jake Hyde though on goal and he lashed the ball past James McKeown.
The Mariners were temporarily shaken by the goal, and were nearly caught out again soon afterwards when Ben Tozer did well to clear the ball to Hyde. His accurate pass down the left found Paul Mullin, who cut inside and hit a twenty-yard drive which McKeown was able to hold onto.
However, Grimsby soon struck back with a pair of quality strikes which turned the game on its head. First, a terrific pass by Hunt opened Wrexham's defence up, the threatening Erico Sousa drove an excellent cross in from the right and Ryan Taylor finished emphatically.
The home side took the lead when a drilled corner from the right was met by the head of Waterfall, who planted the ball firmly inside the far post.
Wrexham finished the half well, however. An extravagant 30-yard volley by Luke Young dipped just wide of the right post, and Hyde thought he'd got another goal when a clever free kick by Young allowed James Jones to whip in a perfect cross for the striker to volley home, but the linesman foiled him by raising his flag for offside.
At the beginning of 4 minutes of added time, Wrexham enjoyed their best sell of possession, ending in Jones driving in a shot from the edge of the area which McKeown saved low to his left.
After the break, Giles Coke had the first effort, pulling a shot wide from the edge of a crowded area, but after that the game descended into a scrappy affair. In truth, The Mariners didn't really threaten again until their third goal in the final minute, and they were allowed to break play up with slow restarts by the referee. Wrexham, for their part, showed little threat up front apart from a period around the middle of the half - their best of the match - when Ryley Towler made a superb double block to deny shots by Hyde and Mullin, and a neat move ended with Liam McAlinden's dangerous cross evading both McKeown and French in the goalmouth.
Substitute Max Wright made a late burst and shot, but his 20-yard effort was smothered by Lainton. However, that run was a warning of what was to come. Wrexham forced a last minute corner as they pushed for the equaliser, but it was cleared easily to Wright, who burst through the middle of the pitch, rounded Lainton and slotted the ball home.
Mullin scooped a late effort wide of the right post in the closing moments, but in truth the game was long gone and Wrexham had to contemplate their first defeat of the season after failing to trouble Grimsby's defence often enough.
GRIMSBY TOWN: McKeown, Efete, Waterfall, Towler, Crookes, Coke, Clifton, Hunt (Pearson 90+1), Sousa (Wright 77), McAtee (Fox 90+1), Taylor. UNUSED SUBS: Revan, Bapaga.
WREXHAM: Lainton, Hayden, Tozer, Cleworth (Green 84), French, J Jones, Young, Redmond ( McAlinden 57), Reckord, Hyde (Angus 77), Mullin. UNUSED SUBS: Dibble, Brisley.
REFEREE: Adam Herczeg
Grimsby Town - Clifton, Sousa.
Wrexham - Redmond, French.
RED CARDS: None.