Grimsby took third place in Sky Bet League Two from Gillingham after beating them 1-0 at Blundell Park.
The Mariners were aided by two red cards for the visitors in the game for Remeao Hutton and Jonny Williams, with Charles Vernam scoring the only goal of the game from the penalty spot in the second half.
Christy Pym was forced to make a crucial save just five minutes in, denying Seb Palmer-Holden one on one.
Hutton was sent off with a straight red card in the 33rd minute for a last-man foul on Jaze Kabia as the Grimsby striker looked to break through on goal.
The hosts were awarded a penalty in the 58th minute, with Kabia the man fouled again in the Gilllingham box, and Vernam converted from 12 yards.
It only got worse for the visitors when Williams was also dismissed in the 63rd minute, receiving two yellow cards in the space of three minutes.
With that, Gillingham were asking too much of themselves to get back into the game as Grimsby emerged victorious.
