Goals from Liam Hearn, Michael Coulson and Anthony Elding helped Grimsby Town comfortably beat local rivals Lincoln.
Conor Townsend's pass found an unmarked Hearn and he calmly put the Mariners ahead before Coulson doubled the lead, heading in another Townsend delivery.
Elding converted a penalty after Jean-Francois Christophe's handball but Lincoln pulled one back through Jamie Taylor's deflected 18-yard effort.
Grimsby's Emmanuel Panther was sent off in the last minute for violent conduct.
Panther was shown a straight red card when he reacted to a late challenge from Tony Sinclair.
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Grimsby Town joint manager Rob Scott told BBC Radio Humberside:
"To pick three points up hot on the heels of three points away against Lincoln is an excellent afternoon's work.
"I'm pleased with the attitude of the players over the two games as it's never easy to win two games against the same team so close together.
"I'm pleased that there was a lot of fans who came out and watched us in numbers and it was pleasing to give them a result at home."
Lincoln City manager David Holdsworth told BBC Lincolnshire:
"I can't hide my disappointment at the manner of the goals we gave away. They were cheap goals and that was the deciding factor because Grimsby haven't outplayed us.
"We've given them the opportunities and they've been victorious because of poor defending and also a cameo role from the referee.
"We played some very attractive football but you can't defend like that. If we'd scored a second they may have given way but it wasn't to be, so we have to take the positives from it and cut out the silly mistakes."