Not sure if this was the case in the OP's story, but the kind of players who intentionally disrespect their opponents tend to have massive egos and don't take losing well.
The worst thing in his mind would be trying his best and still losing against a weaker player, so he'll set up excuses like "I wasn't trying" or "I didn't take it seriously" as scapegoats. If you up your game to the point where you can put the fear of losing into him, his actions and "disrespect" may escalate, but that's because you've got him under pressure and that's his way of dealing with it.
The worst thing in his mind would be trying his best and still losing against a weaker player, so he'll set up excuses like "I wasn't trying" or "I didn't take it seriously" as scapegoats. If you up your game to the point where you can put the fear of losing into him, his actions and "disrespect" may escalate, but that's because you've got him under pressure and that's his way of dealing with it.