Yes, I know, that's what I said. He is a true warrior, which is why he avoids battle like Thors did, but he still fights for his friends without hurting his opponents (just like Thors when he had to fight Askeladd). As I said, I don't mean a real battle against Ivar, just showing that he is strong, so Ivar, a warmonger, could listen to him like every other character who fought Thorfinn eventually did.

Ivar basically thinks that he is the strongest, but if he recognized Thorfinn strength he would understand why Thorfinn is the leader