Grimsby manager Russell Slade felt officials could have shown more "common sense" as his side fell to a 2-0 defeat at home to Coventry.
The Sky Blues took the lead in controversial circumstances as Marc McNulty picked the ball up after Grimsby captain Nathan Clarke had rolled it back to goalkeeper James McKeown at a free-kick.
The hosts insisted Clarke had just rolled it back for McKeown to the set-piece, but McNulty went on to bear down on goal before rolling the ball into an empty net to give his side the lead.
Coventry went on to secure their victory when Jack Grimmer headed in from a corner to make it 2-0, while Grimsby midfielder James Berrett was shown a late red card after picking up a second booking.
"It was a tight game all afternoon and there weren't too many chances for either side," Slade said.
"It was a war of attrition across the middle of the park in many ways.
"We received a free-kick inside our half, Clarkey (Nathan Clarke) has just given it back to Macca (James McKeown) to take the free-kick, and the referee hadn't blown his whistle but deemed that the ball was back in play.
"Clearly from a professional or a fair play point of view, that's all he was doing, passing it back to our goalkeeper to take the free-kick.
"He hadn't blown the whistle - I'm not sure he has to, but certainly there should be a little bit of common sense.
"It is what it is, these things happen, we've made a mistake. From there on is a learning curve for us on where we need to be better in terms of getting back on the front foot."
Meanwhile, Coventry manager Mark Robins believed there was nothing wrong with his side's opener, and felt they were deserving of their win.
"I think we will grow as a team," Robins said.
"We grew into that game and, for the last 10 minutes of the first-half, we were on top. We didn't really want the half to finish.
"You could sense a goal coming, and it was a relief when one came.
"We started to pick things up, and perhaps could have scored twice before the goal. We might have also had a penalty when Jodi (Jones) went down.
"He did fantastically well against both full-backs. As a team, we started to grow into it.
"For the goal, Marc McNulty was brighter than anyone else on the pitch, and that is what we want.
"There was a furore around the goal, but what we saw was Nathan Clarke put his hand on the ball, and that was deemed as though he has taken the free-kick.
"Grimsby were incensed by it, but we didn't see what was wrong."