An angry Steve Evans was sent off as his 10-man Mansfield side were soundly beaten 3-0 at Grimsby.
A Calum Dyson double and first-half goal from Chris Clements saw the home side ease to their first win in five Sky Bet League Two games.
Grimsby took the lead when a scramble in the penalty area resulted in Tom Bolarinwa's header being cleared off the line, but only to Clements who bundled the ball home.
Sam Jones had a great chance to double the advantage after the break when Mansfield goalkeeper Jake Kean missed Clements' long ball forward, but Rhys Bennett got back just in time to block the midfielder's shot.
But Grimsby got their second when Dyson took the ball out on the right before charging his way into the box and finishing superbly beyond Kean.
Things went from bad to worse for Mansfield when manager Evans was sent to the stand before clashing with Blundell Park security staff.
Hayden White then saw red after bringing Bolarinwa down in the box, with Dyson converting from the spot to secure Grimsby's victory.