Croatia coach Niko Kovac said his players "better give it up now and go home" after Brazil were awarded what looked to be a soft, and crucial, penalty in their 3-1 win in the World Cup opening game.
With the match tied at 1-1 in the second half, Japanese official Yuichi Nishimura awarded Brazil a contentious spot-kick when striker Fred went down after a light touch from Croatia centre-back Dejan Lovren.
Kovac called the penalty "ridiculous" and said Nishimura was not at the level to be a referee on the sport's biggest stage.
"If that was a penalty, we should be playing basketball," Kovac said. "Those kinds of fouls are penalised there.
"That is shameful, this is not a World Cup referee. He had one kind of criteria for them and another for us. The rules were not the same."
Even the home fans didn't think the incident deserved to be a penalty, according to Kovac.
"I don't think anybody, anywhere in the stadium, saw this as a penalty," he said. "If you continue like this you will have 100 penalties. I think 2.5 billion people watching on TV saw this was not a penalty.
"This was ridiculous and if we continue in this way we will have a circus.
"Fred is an 85-kilogram [187-pound] man and I don't believe he can be brought to the ground in such a manner."
Brazil coach Luiz Felipe Scolari disagreed with Kovac's viewpoint.
"Millions didn't see the penalty? The referee did and he said it was a penalty and they are the ones that must decide, Scolari said. "We also think it was a penalty. I have seen it 10 times and I think it is a penalty."
Kovac said he did not feel confident about his side's chances to advance if Nishimura's officiating becomes a pattern.
"We better give it up now and go home," he said. "We talk about respect, Croatia didn't get any."
Peter Walton, the general manager of the Professional Referee Organization, which provides officials for Major League Soccer, told ESPN the contact was not enough to warrant a penalty.
"While we can see the slightest of contact between the two players, I would deem the contact to be incidental and this is not enough in my opinion to warrant a free kick or in the instance a PK . I would be disappointed if one if my PRO referees awarded a PK on a similar play."
In more tempered tones, Croatia winger Luka Modric also said he disagreed with the decision, and added that he felt his side deserved a draw against Brazil
"It's difficult. I don't know what to say. I think we played really good. At least we should get a point from this game," he said. "I think we didn't deserve to lose this game but it's how it is. We can't do anything. It's finished now. We need to look forward to next game and try to win next game.
"I don't like to talk about referees. You cannot do anything, it's his decision. I don't agree with the decision. I don't think it was [a] penalty. For sure it was not [a] penalty. But he saw differently and that's what mattered in the end."