Promotion-chasing Forest battled with relegation-threatened Grimsby in a four-goal thriller as Paul Hart's men salvaged a point in the last minute of a well-fought contest.
Despite the difference in league position of these two teams it was hard to tell them apart in the opening 20 minutes, as the visitors defended with some confidence.
However, it was only a matter of time before Forest took the lead and they eventually did so midway through the first half when they were awarded a free kick 30 yards out.
Riccardo Scimeca slotted the ball to an eager Andrew Reid whose venomous shot took a wicked deflection off the Grimsby wall before nestling in the net.
Forest's on-loan striker Darren Huckerby was denied in the 36th minute by the woodwork as he shot form a tight angle on the right.
Grimsby drew level two minutes before the break against the run of play with their first real attack on the Forest goal.
Darren Mansaram did well to make it to the byline and cross to the unmarked Paul Groves who side-footed home from six yards out.
Surprisingly the Mariners shocked the home supporters when they took the lead in the opening minutes of the second half.
Darren Ward punched the ball clear only for it to fall to a goal-hungry Alan Pouton who found the net with ease.
Forest picked up the tempo after Grimsby's second goal and pressurised the visitors, but were denied by some excellent defending.
On the hour mark Forest grazed the visitors post for the second time in the game as John Thompson headed just wide.
Minutes later Forest boss Paul Hart made the decision to take off one of his defenders and bring on the division's top goalscorer David Johnson.
After taking the lead Grimsby utilised every free kick, goal kick and throw in to run down the clock.
However, Forest's dogged determination paid off in the 90th minute as their captain, Gareth Williams, scored from close range after being set up by Marlon Harewood.