The remedy is simple: Be quiet.
It's the first impression. I've seen a pregame-chat in low elo (Silver II) when I was smurfing 2 days ago which were like that (not the real name btw):
bashslayer98: hey guys let me mid
bashslayer98: im good at mid
bashslayer98: its promo
bashslayer98: SYNDRA PLZZZZZZZZZZ
bashslayer98: I WANT MID
And holy moly - this is annoying. Just because you were good in your last game, it doesn't mean you're good in EVERY game. I played AP Thresh, went 10/0, doesn't mean i can play that at the lcs now. If you start the game like that (or even less annoying, it's still annoying), people are more likely to flame, blame or even troll you because they just think: "Well, we lost anyways. Let's completely troll this annoying guy."
On the other hand, keep your head down ingame. You ever heard the term: "Don't feed the troll."? The same applies here. If you rage in the chat, he gets exactly what he wants. He WANTS to annoy you, he WANTS you to be pissed off and mad. If you just don't react to his actions ingame, he will soon lose interest in his actions and may start playing properly. I had a 0/8 xerath once who was a completey dick in chat, nobody responded to his actions and in the end, he played normally and we won the game. Still reported him after the game though for being a dick, but having such a guy in your team doesn't mean you've lost the game.
But in the end, everything you can do is just ignore and report them. There is no "remedy" or something, just ways not to feed him. Just play and do your best. Pick something with snowball potential if you can (Tip: Learn talon, even a onehanded player could carry with him) or simply do your best.