A man was seriously injured when rioting broke out between spectators during a boxing match involving a Leeds fighter.
The victim was taken to hospital after being attacked at the entrance to Barnsley Metrodome, where Damo Jones was fighting Simeon Lucas.
Trouble broke out in the crowd half way through the British Masters Bronze light-middleweight title bout and escalated to a mass brawl involving dozens of fans.
Despite pleas from Jones and the master of ceremonies, the fight had to be abandoned as seats, bottles and other missiles were thrown between rival supporters.
Police were eventually called after numerous people were left injured. By the time they arrived the Metrodome had already been badly damaged.
Tension had started the moment Jones entered the ring to fight for his first professional title fight.
His fans and the home-based Barnsley fans started goading each other from the first bell and things turned ugly in the third round as both sets of fans charged each other.
Shocked ringside spectators found themselves keeping one eye on the action and one eye on the scary incidents that were taking place in the stands as they worried for their safety and well-being.
Women and children were caught up in the fracas.
South Yorkshire Police are investigating.