Do not fall into the stigma that you require a high tier character to fight another high tier character. I've seen many skilled fighters use mid-tier based characters to kill hihgh-tiers. 

It's a bad stigma to follow. Join the fight. You are apart of the Arena group. You have allies who can help and assist you in midcombat. And you have people that you, yourself, can help.

Join the fight, have fun.