The guy claims he was knocked unconscious but says that didn't stop Chris from continuing the attack ... he says CB ruthlessly stomped on him as he lay passed out on the club floor.
In the docs, Diaw claims he had to be hospitalized as a result of his alleged injuries ... which he says include cuts on his head and torn ligaments in his leg.
Chris' accuser says there's surveillance footage of the whole thing ... and he says cops in London have the alleged beatdown video. Diaw claims he can identify Chris in the footage and claims CB is a fugitive in the United Kingdom as a result of the alleged incident.
And, get this ... Diaw claims he's known Chris for at least seven years and thought Chris was coming up to hug him at the club when Brown instead allegedly struck him three times with the tequila bottle.
Diaw says his injuries may be permanent and he's suffering serious emotional distress and trauma. He's suing Chris for damages.
We reached out to Chris' camp ... so far no word back.