fight fire with fire 以火攻火；以毒攻毒；以其人之道还治其人之身

【例句】
Kurosawa's peasants decided to fight fire with fire.
黑泽明电影中的农民决定以其之道还治其身。

The only way he could beat his opponent was to fight fire with fire and be equally aggressive.
他要想打败对手，唯一的方法就是以牙还牙，和对方一样大胆进攻。