Grimsby Town extended their unbeaten run to 14 matches in all competitions with victory at Lincoln City.
The Mariners took the lead when Ross Hannah headed home Scott Kerr's inswinging corner.
Luke Foster almost levelled for the Imps when he headed Alan Power's free-kick against the bar.
Craig Disley made it 2-0 with a diving header but was then the victim of a bad 89th-minute challenge by Lincoln's Jake Sheridan, who was sent off.
VIEW FROM THE DRESSING ROOM
Lincoln City manager Gary Simpson told BBC Radio Lincolnshire:
"They're third in the table, full of confidence and going very well. We've got one or two who perhaps shouldn't have played and one or two on the bench who would have struggled if they'd gone on, but we kept going, gave everything from the first to the last minute and if we keep working as hard as that, surely things have got to turn sooner or later.
"At half-time we were battering them but were 2-0 down and that's how we've been recently. I thought we more than matched them at times today. They had a couple of chances and took them and their keeper pulled off some terrific saves.
"I'm just disappointed for the supporters, it's a local derby and they came out in their numbers so I'm disappointed for them. The players put their bodies on the line, they tried and tried and we just needed a goal. If we'd got one then momentum might have seen us through but we just couldn't get the goal."
Grimsby Town manager Paul Hurst told BBC Radio Humberside:
"It started off at a frantic pace, very similar to last year... but it wasn't a great game to watch, I don't think, but I'm happy to get the three points.
"There's no doubt we didn't play as well as I would have liked by a long shot.
"You have to win all different ways and we are capable of that, but I would like us to play more football. It's a bit ironic that we've won the game from two set-plays when we've defended numerous long throws, corners and free-kicks. It wasn't one for the football purist."
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