A Copa Libertadores tie between Boca Juniors and Guadalajara was abandoned in the second half after a supporter attacked a player, fans hurled missiles onto the pitch and the teams fought amongst themselves.
Play at Boca's Bombonera stadium was halted with the score at 0-0 in the 79th minute of the quarter-final, second leg tie.
The Mexican side won the first leg 4-0.
Referee Martin Vazquez waited 20 minutes before attempting to restart play, then called the game off almost immediately as a mass of fans gathered ominously behind the Guadalajara goal.
They were apparently preparing to pelt visiting goalkeeper Jesus Corona or scale the fence and invade the pitch.
Television pictures showed Corona with an expression of sheer terror on his face as he walked back to the goal in front of the three-tier stand, ready for the restart.
Almost immediately the game was abandoned.
Trouble initially broke out following one of several brawls on the field.
Boca midfielder Raul Cascini appeared to head-butt Guadalajara striker Adolfo Bautista as the two challenged for the ball, Bautista fell to the ground and when he got up, he was surrounded by angry Boca players accusing him of acting.
Boca striker Martin Palermo chased Bautista and both were sent off, although the Guadalajara player appeared to do nothing more than try to run away.
Palermo initially refused to leave the field and was seen to poke the referee and head-butt Bautista before being escorted away.
Meanwhile, Bautista was pelted with missiles as police led him around the touchline towards the dressing-room while objects were also thrown at the Guadalajara team bench.
As Bautista passed behind the Guadalajara goal, a fan who managed to scale the five-metre fence around the field punched him from behind.
He climbed back over the fence and into the crowd to the approval of other supporters and police were unable to catch him.
Almost immediately, goalkeeper Corona appeared to be struck by another missile thrown from the crowd.
The players were then taken to the centre circle as the referee and police decided what to do next.
Meanwhile, a number of fans climbed to the top of the fences around the pitch, threatening an invasion.
Eventually, the referee decided to suspend the tie and the final outcome will now be decided by the South American Football Confederation (CSF).
Boca were already smarting from their first-leg defeat even before Guadalajara's flamboyant president Jorge Vergara raised the temperature on the eve of the game by claiming that his team were going to win 2-0.
Boca clearly tried to intimidate the visitors from the start of the game with close marking, rough tackling, constant provocation and gamesmanship, forcing the referee to show seven yellow cards in the first half.
However, they were unable to find a way past Corona, who made several outstanding saves.
This is like 10x worse than what a tiny fraction of the Inter fans did in the euroderby, I wonder how Boca Juniors will be punished.