A Copa Libertadores match between local football rivals Boca Juniors and River Plate has been suspended after River players were attacked by fans with pepper spray.
The second leg of the pre-quarterfinals on Thursday was called off at half-time with the scores 0-0 at the Bombonera stadium, reports Xinhua.
River, who won the first leg 1-0, needed only a draw to progress to the quarter-finals of South America's premier club competition.
"The match between Boca Juniors and River Plate has been suspended. The second half could not restart," South American football governing body Conmebol said on Twitter.
The players affected by the spray were Leonardo Ponzio, Matias Kranevitter, Ramiro Funes Mori and Leonel Vangioni, according to local press reports.
Funes Mori was captured by television cameras screaming: "I can't see, I can't see. I'm burning."