Croatia coach Niko Kovac labelled a controversial penalty awarded against his side as "ridiculous" and warned that the World Cup will turn into "a circus" if referees do not improve.
- Related Content
Japanese official Yuichi Nishimura awarded Brazil a soft spot-kick in the opening match of the tournament in Sao Paulo - the score was 1-1 at the time and the hosts went on to win 3-1.
Brazil striker Fred won the penalty after going down despite being barely touched by Southampton centre-back Dejan Lovren.
Kovac said afterwards: "I don't think anybody, anywhere in the stadium, saw this as a penalty. If you continue like this you will have 100 penalties. I think 2.5billion 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 85kg man and I don't believe he can be brought to the ground in such a manner.
"I cannot blame Fred at all - everyone tries it on. Like it or not, this is part and parcel of football. What I want is for referees to stick to the laws of the game and apply them equally to both teams."
Croatia had opened the scoring courtesy of an own goal by Marcelo, but Neymar equalised and then despatched the penalty, with Oscar getting a third late on.
Kovac added: "I would like to congratulate Brazil as they are a great opponent, but I am proud of my team. I am a sporting person and Brazil were excellent, but I believe Croatia deserved at least a point out of this game."
Neymar stole the show for Brazil , but coach Luiz Felipe Scolari hailed the impact of Chelsea midfielder Oscar.
There have been doubts expressed in the Brazilian media about 22-year-old Oscar's form, but Scolari insisted he had never lost faith.
Scolari, who guided Brazil to be world champions in 2002 and has never lost a World Cup match with the country, said: "Neymar got man of the match, but if there was a second award it should go to Oscar.
"Our statistics after the game shows he was the one who made the most tackles, and made lots of dribbles and crosses - he was our most creative player on the right.
"He was fantastic and that's the kind of player he is and I have always believed in him.
"Any doubts came from your side [the media]. His level may have dropped but I never lost belief in him."
Neymar admitted he had had a dream start to the World Cup.
The Barcelona forward said: "I think I am happier than I ever dreamt, to start with a victory in the World Cup such as this.
"The whole team deserves praise for being able to keep calm and turn things around."