Three second-half goals ensured 10-man Torquay retained their league status and sent Grimsby towards the drop out of the Football League, as Paul Buckle's men ran out 3-0 winners.
After a scrappy first half of just one effort on target - a header from Grimsby's Jean-Louis Akpa Akpro straight into Michael Poke's arms - the Gulls took control.
Their first goal came from the penalty spot on 53 minutes, Nicky Wroe hammering home after Olly Lancashire had tugged down Elliot Benyon in the box.
Benyon got the second himself nine minutes later when he rifled home at the near post after good work from winger Mustapha Carayol.
Defender Guy Branston then saw red on 65 minutes for the Gulls for second yellow card after a foul on Akpa Akpro.
But the visitors maintained a stranglehold and Carayol waltzed through from midfield to coolly slot a third past Nick Colgan on 71 minutes to ensure Torquay's safety.