A 10-man Grimsby snatched victory at Hayes & Yeading to move within four points of the play-offs places.
Rob Duffy fired the visitors in front when he latched on to the end of Michael Coulson's corner to score.
Shaun Pearson's thumping header from Peter Winn's delivery extended the visitors advantage.
The Mariners' Anthony Church saw red when he fouled Julian Owusu in the box, before Jamie Hand converted the resultant penalty to give Hayes hope.
VIEWS FROM THE DRESSING ROOM
Grimsby Town joint-manager Paul Hurst told BBC Radio Humberside:
"Credit to the players, we thoroughly deserved it although we made it hard for ourselves with the sending off.
"The lads have said it probably is a penalty but with the sending off, I'm not too sure.
"There seemed a lot of bodies around but it's one of those you have to live with."
Hayes & Yeading 01 Arnold 03 Moutaouakil 05 Cadmore 30 Spence 39 Walsh 04 Hand 19 O'Brien 20 Lee Booked (Owusu - 63' ) 25 Ajala (Bentley - 89' ) 11 Wishart 27 Collins (Pele - 63' ) Substitutes 31 Beasant 02 Argent 18 Pele 12 Bentley 06 Owusu Grimsby 13 McKeown 15 Pearson 19 Wood 22 Townsend 32 Miller 04 Church Dismissed 07 Coulson 08 Disley Booked 36 Winn (Thanoj - 70' ) 12 Duffy Booked 39 Elding (Hughes-Mason - 83' ) Substitutes 02 Silk 06 Garner 21 Thanoj 40 Soares 33 Hughes-Mason