Blue Square Bet Premier leaders Grimsby were held by rivals Lincoln as both sides ended the match with 10 men.
Alan Power volleyed the Imps into the lead from 20 yards, but they saw keeper David Preece forced off by injury.
And soon his replacement, Paul Farman, was beaten by Ian Miller's header from Joe Colbeck's free-kick to level.
Town had defender Aswad Thomas sent off for violent conduct before a serious foul from 88th-minute substitute Adam Smith reduced the Imps to 10.
The draw means that Grimsby lie just one point above second-placed Wrexham in the table without a defeat in seven league games, while Lincoln lie in 14th.
VIEW FROM THE DRESSING ROOM
Grimsby Town joint boss Paul Hurst told BBC Radio Humberside:
"I think when you consider that we had to finish the game with 10 men and the fact that we haven't played well today then it probably a point gained.
"I still felt when we went forward early in the game we looked like we caused them problems but we were second best to a lot of second balls.
"We didn't pass the ball which is unusual for us. It was a very scrappy game."
Lincoln City manager David Holdsworth told BBC Radio Lincolnshire:
"We wanted to come and win the game and set up to have a go. We spoke a lot about the previous game (against Grimsby) and the individual errors but I've got no problem with my boys today, they did us proud. They're on cloud nine because we've been the better side.
"Our frustration is in the officiating. In the first half, either we should have had a clear goal or the player's clearly handled the ball and the ref and the officials got it completely wrong so we can feel frustration in that but I'm absolutely proud of my players.
"The spirit that's within our camp has been typified by today. There'll be good days and bad days but the Lincoln fans will have seen their team play with pride, passion commitment and integrity today and they'll be going home very proud, I would imagine."