Stadium staff struggled to deal with a serious failure in security measures before Spain's World Cup match against Chile at the Maracana.
Hundreds of Chile fans without tickets broke through fences and climbed over barriers into the stadium.
A number of the intruders who charged through the main media centre were detained by officials but many others appeared to have made their way into the stands after breaking down a temporary wall.
Meanwhile, thousands of Chile fans without tickets remained on the roads outside the stadium but organisers said kick-off would not be delayed.
A joint statement from Fifa and the local organising committee said “at least 85 intruders” had forced their way into the stadium but that none had made it to the seating area for the match.
The statement said: "Ahead of the Spain versus Chile match at the Maracana, a group of individuals without tickets violently forced entry into the stadium, breaking fences and overrunning security. They were contained by the security and did not make it to the seats.
“The situation was brought under control quickly and at least 85 intruders were detained according (to) the military police of Rio.
"The organisers of the Fifa World Cup condemn these acts of violence and we will communicate further information and measures to be taken in due course."
According to Brazilian media, one person – a disabled woman who is a Chile fan – was injured.
Chile went on to shock the defending champions in the first half, scoring through Eduardo Vargas and Charles Aranguiz to lead 2-0 at the break, a result that would see Chile and the Netherlands go through to the second round. .