|
Forest's matchwinner was striker David Johnson who followed on from strike partner Marlon Harewood's treble in midweek with one of his own.
A three-goal haul for Johnson looked unlikely as with just five minutes left Forest were leading 1-0 thanks to Johnson's 17th minute header.
But Grimsby went down to ten men when full-back Tony Gallimore was sent off on 58 minutes for violent conduct and their spirit was broken with the two late goals.
On 85 minutes Johnson was held back by Grimsby player-manager Paul Groves and coolly slotted home the penalty.
That was Johnson's eighth goal of the season and he made it nine in stoppage time with a superb solo effort. Twisting and turning the stretched Grimsby defence he finished off by coolly burying a shot into the bottom corner.
The victory sealed Forest's second away win of the season and inflicted Grimsby's third successive home league defeat.
Forest boss Paul Hart said: "It was a great three points, but it was a bit too bitty and we can do better."