Pandemonium at a Golden Gloves boxing event in L.A. on Wednesday -- when fans stormed the ring at a youth tournament and fought it out ... with one guy catching a haymaker right in the face.
It all went down at a Golden Gloves qualifier tournament at a rec center 2 miles from Dodger Stadium -- when fans got pissed after an alleged late punch during a bout between teenagers.
One witness tells us people began to scream at each other -- then they stormed the ring -- then the punches flew.
The witness adds, "Chairs were thrown and people were hit with chairs.