fight fire with fireto use the same methods as your opponents in an argument, competition
[TahlilGaran] Dictionary of Contemporary English ▲
fight fire with fire v. phr.,
slightly formal,
of Biblical origin To fight back in the same way one was attacked; make a defense similar to the attack.
The candidate was determined to fight fire with fire in the debate. [TahlilGaran] English Idioms Dictionary ▲