Counter-heroes in duel mode (3.1).

I have the following question. In a duel, Iris is practically unbeatable. I was only able to defeat her with Ravenna, and even then, only once. I heard that Deidre is a good counter, but I'm very skeptical because Iris has decent resistance. Can anyone share their experience and name a counter that defeats her 100%?

Yes, there's also Ossir, but frankly, he's just as overpowered, so please don't use him as an example.