The bitter rivalry Argentinian soccer teams Boca Juniors and River Plate took a violent, bitter turn on Thursday at the Conmebol tournament.
The melee started when Boca fans doused a tunnel with peppers spray or mace as members of the rival River team entered the field.
River players stumbled onto the field to start the second half of the scoreless match covering their faces, rubbing their eyes, and dousing themselves with bottles of water, the Associated Press reported.
River said in a statement that at least four players were diagnosed at the hospital with inflamed corneas, while several more suffered burns from the spray.
Former Argentine player and manager, Carlos Bilardo, told local television that Thursday's episode was not the first:
In New York, Italy or England, [violent cases like this] have been worked out by entering in the stadium and taking out those who commit this crimes. This is not an isolated case, this has been going on for a long time and it has to end.
On Friday, fans reacted with the hashtags #MatanAlFutbol (#TheyKillSoccer) and #SuperVergüenza (#SuperShame), which trended on Twitter in Argentina.
Attackers were labelled as "maladjusted" and "unpunished" — among other derogatory terms — in a nation where soccer reigns supreme.
Some fans have been debating online what was really behind Thursday's episode, including whether it was planned well in advance.
Some people even compared the tunnel incident with Cromañón, a nightclub where 194 people died in 2004 after someone lit a flare inside.
In drawing the comparison, fans point to the "one person" who lit the flare in Cromañón, and the "one person" seen throwing pepper spray or mace into the stadium tunnel.