An attack on the Boca Juniors team bus by River Plate fans left Boca players coughing and teary eyed amid the glass of smashed windows ahead of the Argentine giants' "superclasico" Copa Libertadores final second leg on Saturday.
A group of River fans pelted the bus with stones and gas as it arrived at the Monumental stadium in the upmarket Nunez neighborhood of Buenos Aires.
Television pictures showed Boca players emerge from the bus, which had several broken windows, clearing their throats and with eyes streaming from the effect of the gas.
The attack came despite the bus travelling with heavy police protection ahead of the second leg of the local derby between the two teams -- dubbed the biggest club match in the history of Argentine football.
The final of the Copa Libertadores, the equivalent of Europe's Champions League, is finely poised at 2-2 following the first leg at Boca's Bombonera stadium two weeks ago.
There will be no Boca fans at the second leg as travelling support has been banned at all Argentine football matches since 2013 due to hooliganism.
Football-related violence has cost the lives of more than 300 fans in Argentina over the last 50 years, according to figures from the Salvemos al Futbol (Let's save football) charity.
This local encounter is widely viewed as the fiercest rivalry in world football.
