Grimsby missed the chance to move into the Conference Premier play-off places after drawing 0-0 with Southport.
Aristote Nsiala could only head over from John O'Sullivan's cross as the visitors looked to open the scoring.
Craig Disley was off target with a header of his own at the other end, before Alex Rodman missed another chance to give the home side the lead.
Paul Hurst's side improved after the break but Ross Hannah and Lenell John-Lewis were both denied.
VIEW FROM THE DRESSING ROOM
Grimsby boss Paul Hurst told BBC Radio Humberside:
"It was far from a classic, but I still think that without being at our best, we had some good chances to win it.
"We had one cleared off the line in the first half and then in the second half we had four good chances.
"They gave it a go and we created opportunities, particularly towards the end of the game."
Southport manager John Coleman told BBC Radio Merseyside:
"I'm pleased for the players and the fans that made the trip. I've got to thank them for their efforts and I think they were rewarded with a battling performance by the players.
"We more than deserved the point. Danny Hurst has made a couple of great saves but that's what we've limited them to.
"We had our own chances but we were a little bit wasteful in front of goal."
Grimsby Town 13 McKeown 27 Fyfield 05 Pearson Booked 15 Bignot 12 McDonald 11 Neilson (Colbeck - 64' ) 23 Rodman 08 Disley 04 Kerr 14 John-Lewis (Cook - 79' ) 17 Hannah (Tounkara - 71' ) Substitutes 09 Cook 07 Colbeck 28 Tounkara 02 Hatton 18 Thanoj Southport 01 Hurst 28 Daly Booked 20 Fitzpatrick 07 Nsiala Booked 27 O'Sullivan 06 Brown 18 George 10 Ledsham 30 O'Neil 15 Hattersley (Mukendi - 72' ) 25 Brodie Booked (Osawe - 46' ) Substitutes 08 Mukendi 19 Wimmer 29 Dillon 05 Flynn 21 Osawe
Ref: Adrian Holmes