Quinton ‘Rampage’ Jackson's Son Raja Brutally Attacks KO'd Wrestler, on Video

Raja Jackson, the son of former UFC light heavyweight champion Quinton "Rampage" Jackson, went beast mode during a match Saturday night ... violently attacking his competitor with blows to the head despite him already being knocked out.

The disturbing footage from the event's Kick livestream shows the victim -- Stuart Smith, whose ring name is Syko Stu -- being slammed to the ground ... a move that seemingly knocked him out cold. Raja then mounts his unresponsive body, delivering hit after hit until he's pulled off.

The incident occurred at a private wrestling event by KnokX Pro Academy in Los Angeles, and according to wrestling reporter Sean Ross, Syko ended up in the hospital.

Ross claimed on X Saturday the spot was planned, but the heavy blows "were not planned to do that kind of damage."

Raja's famous father claimed in an X post that Syko did wake up after the violent KO and is in "stable condition" while also apologizing for his son's actions.

Explaining the situation, he allejed Raja was "unexpectedly hit in the side of the head" by Syko moments before the match, and "Raja was told that he could get his 'payback' in the ring."

A video circulating online shows Syko Stu smashing a can into Raja's head ... nearly making the opponents go at each other before the main fight.

Interestingly, clips from the Kick stream also show the pair making up and shaking hands before they faced each other in the ring.

However, Rampage did not condone his son's continued hits during the ring battle, writing ... "Raja is a MMA fighter not a pro wrestler and had no business involved in an event like this. ... He suffered a concussion from sparring only days ago and had no business doing anything remotely close to physical contact."

He added he's "deeply concerned" with his son's health and Syko's, adding ... "I’m very upset that any of this happened, but my main concern now is that Mr. Smith will make a speedy recovery. I apologize on his behalf and to KICK for the situation."