Colchester United came out victorious, grabbing a 2-1 win in front of almost 1,000 U's fans at the JobServe Community Stadium, with Tommy Smith and Callum Harriott on target.
Steve Ball named a side with four changes from the eleven that played out a 1-1 draw against Crawley Town in the week.
Tommy Smith, Luke Norris and Luke Gambin all returned to the starting eleven, with sixteen-year-old Junior Tchamadeu making his first ever professional start, coming in for the suspended Miles Welch-Hayes at right-back. Omar Sowunmi returned to the bench, as did Kwame Poku, with Ben Stevenson also missing out through suspension.
There was a fantastic welcome back to the pitch for the players as the U's crowd cheered their players for the first time at the stadium since February.
And it didn't take long for the players to give them something to cheer about.
Tommy Smith opened his Colchester United account eight minutes in when he bundled in a Courtney Senior corner, as McKeown failed to palm the ball away from goal.
But it was a lead that wouldn't last. The visitors got themselves back level after twenty minutes.
Dean Gerken pulled off a brilliant save to deny Bennett at the back post, pushing the ball wide and out for a corner. The ball was then whipped across the near post with Hendrie getting the flick on and guiding the ball into the far corner to make it 1-1 in front of the South Stand.
The U's would count themselves unlucky to not be given a penalty kick with ten minutes of the half remaining. Noah Chilvers' perfectly weighted chipped through ball found Harriott who raced away from Pollock before being shoved to the ground in the area, with the referee and linesman both saying nothing.
There was little else to separate the two sides before the break, the only action being Sean Scannell coming off injured for the Mariners just before the break and being replaced by George Williams.
Steve Ball's side came out fighting in the second half, with the added incentive of kicking towards the South Stand with fans for the first time this season.
And the addition of almost 1,000 chanting U's fans seemed to work, with Callum Harriott firing his side back in front ten minuted in to the second period.
Harriott made it two goals in two games as he danced through the Grimsby defence before aiming a low shot powerfully beyond McKeown to make it 2-1 to Colchester United in the fifty-sixth minute.
Grimsby were pressing for a second equaliser and went very close to finding it though centre-back Luke Waterfall. A dangerous ball eluded everyone except the Grimsby man at the back post who had a tougher job of missing the target as he lofted the ball just over the bar from inside the six-yard box.
The Mariners kept pressing and almost found a breakthrough with less than ten minutes to play. Luke Norris was the man making the block as he slid in to deny Terry Taylor whose powerful effort looked to be heading in.
Montel Gibson then saw a similar effort blocked, this time by Tom Eastman who put his body on the line to prevent the Ian Holloway's men from grabbing a late equalier.
And the Mariners were pressing everything forwards, even goalkeeper James McKeown up for a corner, but they were unable to produce anything as the final whistle blew with a great cheer going up in the stands as the U's picked up another home win.
It is a result that pushes the U's up the table to ninth and sitting just a point outside the play-off places with their game in hand to be played next, up against Scunthorpe on Tuesday evening.
Colchester United starting XI: Gerken, Bramall, Smith, Senior (Poku 86'), Norris (Sowunmi 90'), Brown (Folivi 80'), Harriott, Chilvers, Eastman, Gambin, Tchamadeu.
Unused subs: George, Scarlett, Marshall Miranda, Bohui.
Grimsby Town starting XI: McKeown, Hendrie, Preston, Rose, Waterfall, Windsor, Scannell (Williams 45'), Edwards, Pollock (Taylor 77'), Hewitt, Bennett (Gibson 82').
Unused subs: Battersby, Clifton, Starbuck, Idehen.
