Boca Juniors fans are renowned as some of the most passionate in world football.
The two teams met Sunday at Boca's La Bombonera Stadium, but the eventual 1-1 draw was held up for 15 minutes in the second half as the home supporters reacted in fury as River Plate manager Ramon Diaz was escorted off the field following his dismissal for allegedly insulting the referee.
River Plate opened the scoring through midfielder Manuel Lanzini after just 45 seconds of the match, but Boca's Uruguayan striker Santiago Silva levelled six minutes before the half-time whistle.
However, in the second period, referee German Delfino dismissed the River Plate boss, and Diaz was accompanied by riot police on his walk back to the dressing rooms as home supporters threw flares and objects on to the pitch.
Some fans climbed the steel fences separating them from the players and the pitch, and police responded by firing water cannons (BBC Sport).
Boca Juniors have struggled in the league this season, while their neighbours are challenging for the Argentinian title.
They are four points behind surprise league leaders Lanus, who have 26 points, while second-placed Velez Sarsfield have 25 points.