Morecambe boss Jim Bentley was left frustrated after a late Grimsby goal denied his side a fourth successive home win.
Charles Vernam’s goal two minutes from time was Grimsby’s first in five games and secured a 1-1 draw, after Aaron Collins had given the home side an 80th-minute lead.
Bentley said: “It could have been a win. It should have been a win. But it wasn’t and we are all a bit frustrated.
“A win would have virtually secured our safety for another year so it was a bit of a blow but we are still in a good spot, 10 points clear with four games to go and we have to be happy with that.
“Overall it was a bit of a strange game but we got the penalty which was a bit of luck for us that we were grateful for to give us the lead.
“But they made a technical change and pushed bodies forward and got their reward with a goal back which we didn’t defend particularly well. Late goals have killed us this season, though, and to see it happen again was really frustrating.
“We were desperate to win the game and the three points would have been a massive boost for us.”
Morecambe started brightly, with Liam Mandeville firing wide after just four seconds before Kevin Ellison volleyed over from the left side of the box.
After a sluggish start Grimsby began to find their feet, with Barry Roche saving smartly from Luke Hendrie and Joe Grayson, and the latter missed a great chance to score in the 31st minute when he was found free in the box, but shot well over the top.
Aaron Wildig then went close with a curling chip that was inches too high with time running out.
The second half was much quieter until a frantic final 10 minutes.
Collins put the Shrimps 1-0 up 10 minutes before the end from the penalty spot after he had been brought down by Grimsby keeper James McKeown.
Collins sent the keeper the wrong way but Michael Jolley’s side hit back as they pushed bodies forward and Vernam slotted home a right wing cross from six yards out to earn the Mariners a share of the spoils.
Grimsby boss Jolley praised his side’s character after their late fightback.
He said: “We played well in the first half especially and I think it was fair to say we were disappointed that at the break we didn’t have the lead but our nemesis of not scoring when we are doing well came back to haunt us.
“The second half was more even and we have conceded a penalty which I don’t really want to talk about apart from saying it wasn’t a penalty.
“But then we showed really good character and scored a good goal. We made some changes and they all made an impact and I’m really pleased for Charles Vernam as he was our best player today and deserved his goal.”