A Copa Libertadores clash between fierce rivals Boca Juniors And River Plate was abandoned after fans pepper sprayed the players.
Boca Juniors supporters, who are known for their hatred of their Buenos Aires rivals, seemed to spray the substance towards the River players when they emerged from the tunnel at the start of the second-half.
The game, which was being played at Boca's Bombonera stadium, was the second leg in the South American equivalent of the Champions League, with River leading 1-0 from the opening encounter.
Players began suffering problems with their vision and attempted to relieve themselves of pain by washing their faces with water on the pitch.
Four players - Leonardo Ponzio, Leonel Vangioni, Matias Kranevitter and Ramires Funes Mori - were taken to hospital to be treated for burns.
The game was called off after around half an hour of the players being kept on the pitch, until they were eventually escorted back to the dressing rooms under police guard, as fans threw a variety of objects at the visiting River Plate team.
Boca fans also launched a drone carrying a 'B' banner to indicated River's recent relegation to the Argentine second tier, something which the home supporters were more than happy to highlight.
The two sets of supporters are known for their passionate support, which has seen plenty of clashes between the two factions over the years.
Boca president Daniel Angelici said after the match: "We will accept the responsibility that we have but I don't think the players are responsible.
"We will do all we can to help the police and we hope to find those responsible as soon as possible.
This is society's problem, not football's problem. These people are sick."