He is my go-to when i play clash lane for he can go toe-to-toe with almost every fighters in early game but mayene was his counter for her mobility and burst damage
I would say it depends on mayene pilot and your knowledge, just keep distance and do not go near bush, but I only encounter mayene once so you could ignore my advice and yep I bully her in clash line
I have many times against Arthur, i would say we are equal, unless you build your dun right then you will win, it was a hard fought🙃. Did you know skill 2 dun actually deal more damage to jungle monsters? I would suggest you try to steal some jungle but do not steal enemy buff early you takes too much time