二虎相斗，必有一伤

lit. when two tigers fight, one will get injured (idiom); fig. if it comes to a fight, someone will get hurt

lit. if two tigers fight, one will get injured (idiom); fig. if you start a war, someone is bound to get hurt

lit. two tigers fight (idiom); fig. a dispute between two powerful adversaries; a battle of the giants

lit. two tigers fighting (idiom); fig. fierce contest between evenly matched adversaries

lit. the mountain can't have two tigers (idiom); fig. this town ain't big enough for the two of us

lit. either the fish dies or the net gets torn (idiom); fig. it's a life-and-death struggle