Watching the replay on Youtube, I thought it was more a situation of Kimbo trying to shoot in on the guy's weak leg lick, and having it pulled out from under him, which dropped him to the mat, where he was pounded on until the fight was called. He certainly didn't look dazed as he dropped, more of a "oops" moment.
That said, I've never been particularly impressed by Kimbo, even on his bare knuckle fights that made him "famous". Yeah, he looks badass, and he's got a solid punch, but he's slow as hell.