Grimsby boss David Artell felt a “horrific” refereeing decision cost his side dear in their 1-1 draw at Sutton.
Justin Obikwu fired the visitors in front on the stroke of half-time.
But the Mariners squandered a number of chances to put the game to bed before an 88th-minute Charlie Lakin penalty, for handball in the box, rescued a point for the Football League basement boys.
But Artell, whose side are five points clear of the drop zone, said: “I thought the game should have been done and dusted and we should have wrapped the game up long before we’ve been on the end of a horrific refereeing decision so we’ve only got ourselves to blame.
“We don’t want to see referees like that.
“I was generally pleased with the performance. If that game had ended 3-0 I don’t think anybody would have complained.
“But it didn’t. The longer the game went on the more you give them a chance to get back into it.
“They had some balls into the box and some blocks, some headers and stuff. I didn’t particularly feel we would be opened up and we didn’t.
“We were just on the end of a horrific decision. It happens.
“It feels like two points dropped because we were by far the better team.
“If we had our shooting boots on then we would have been out of sight long before the last 10 minutes.”
Sutton secured a point in the right direction to leave themselves five shy of safety with nine games to go.
And boss Steve Morison said: “It’s the worst we’ve played, but we stuck at it and got a point.
“I’m frustrated with the performance. The pressure got hold of us a little bit and we didn’t handle it very well.
“We were second to too many balls. But credit to the players we stuck at it.
“We needed some big saves from Arnie [Steve Arnold] at times. It looked like it wasn’t going to be our day, but I’m pleased we’ve managed to get a point out of the game.
“You have to try and find the positive and that’s the positive for today, that we’ve got a point from that performance.
“It’s a stonewall penalty, I know they’re going to be upset about it and we’ll say it’s a penalty, but that’s just life.
“We just weren’t good enough, but I’m pleased we’ve not been good enough and got a point. I’d have been gutted standing here if we had lost because our performance didn’t deserve anything, but I’m pleased we got something.”