diamonds cut diamonds 棋逢对手，将遇良才，强中自有强中手

【例句】
It's always diamond cut diamond when those two schemers get together.
当这两个谋士聚在一起时，总是棋逢对手。

The two cats challenged each other for the disputed territory -it was a case of diamond cut diamond.
两只猫为争地盘而互相挑战——真是棋逢对手啊。