The action wasn't just on the court at the famous McDonald's All-American high school hoops game Wednesday ... a huge brawl broke out in the concourse and it was all caught on video.
FYI, the McDonald's game is a BIG DEAL in high school sports -- bringing together the top prep players in the country ... almost all of whom are already serious NBA prospects.
But after the final buzzer, roughly a dozen people went to war in the 300 level of the United Center in Chicago -- throwing haymakers and slamming each other to the floor.
Fortunately, in video obtained by the Chicago Sun-Times, you can see multiple security team members rushing in and breaking the whole thing up.
Event organizers later issued a statement saying they're disappointed -- but "we are equally grateful to the United Center Security team and the Chicago Police for restoring order."