两虎相争必有一伤的英文：
[Literal Meaning]
two/tiger/mutual/fight, must/have/one/injure
When two tigers fight, one of them must be injured.

[解释]
两只老虎互相争斗。比喻力量强大的双方相搏斗，肯定有一方会失败。

[Explanation]
When two strong forces are in conflict, one must be defeated.

[例子]
两虎相争，必有一伤。果然一个武术家被另一个打倒了而且骨折了。

[Example]
When two strong forces are in conflict, one must be defeated. Inevitably a martial artist was knocked down by the other and one of his bones was broken.

[英文等价词]
to meet one's match