Port Vale’s nine-game unbeaten run was brought to an end as Matt Green’s goal proved enough to give relegated Grimsby a 1-0 win.
After a sedate half-hour, some life was finally injected into the game when Luke Joyce’s under-hit pass back to his goalkeeper was pounced upon by Green before he placed it into the far corner of the net.
Vale came close to levelling things before the break, with Cristian Montano forcing Jake Eastwood into a decent save on the turn before Theo Robinson skied his effort on the follow-up.
The visitors should have brought themselves level when David Worrall went one-on-one with Eastwood early in the second half, but the on-loan Sheffield United goalkeeper did well to block the effort.
Port Vale continued their search for an equaliser as Tom Conlon forced substitute goalkeeper James McKeown into a good save before Nathan Smith saw his header cleared off the line.
Devante Rodney struck the post before Tom Pope was denied by McKeown, but Vale’s hopes of rescuing a point were extinguished when Montano received his second booking late on and was given his marching orders.