Alright, so I also have an annoying friend problem. I usually stomp him in versus using most characters, but then he starts tunnel visioning and is set on me. Example: He has an opportunity for a double kill or a single kill on me, he goes for me. He's a real big trash talker, t-bagger, only plays the cheapest characters, and spams like a madman. So this isn't really asking for help, more like you all decide how I shall punish him?
When you know you have more kills than him and you know you're going to win, just run away from him until the match is over. I'd recommend using character with good mobility like Jak or Kat.
He likes to play on stock, with high AP too, it's kinda the only reason he can actually get kills and win sometimes .