An attack on the Boca Juniors team bus by River Plate supporters has led to the postponement of the final of the Copa Libertadores second leg.
The game between the two fierce Argentine rivals will now take place on Sunday at 20:00 GMT in Buenos Aires, 24 hours later than originally scheduled.
The announcement - made by River Plate on Twitter - came after more than two hours of confusion at River's Monumental stadium, during which the kick-off was put back twice - first to 21:00 GMT and then to 22:15 GMT.
According to reports in Argentina, Boca players suffered cuts from the glass from broken windows and were also affected by the tear gas used by police.
A number of players, including Boca's former Manchester City striker Carlos Tevez, were reportedly suffering from dizziness and vomiting and being treated by club doctors.
Footage apparently from inside the Boca dressing room showed the players groggy and disorientated.
Reports said Boca's Pablo Perez and Gonzalo Lamardo had been taken by ambulance to hospital, the former with slivers of broken glass in his eyes and the latter a cut on his head.
The attack occurred as the team made its way to River's Estadio Monumental in Buenos Aires.
Former Argentina striker Gabriel Batistuta branded the scenes "shameful", saying on Twitter: "Another opportunity lost in front of the whole world that observes us, shameful, lamentable."
The Copa Libertadores is the showpiece club competition in South America, equivalent to the Champions League in Europe.
Three years ago, a last-16 Copa tie between River and Boca at the latter's La Bombonera ground was abandoned at half-time after Boca fans attacked the River players with pepper spray in the tunnel.
Boca were kicked out of the competition, while River were given a bye into the quarter-finals.