There's nothing you can do about it unless you get a ninja with genjutsu mirror like Kurenai, etc. You're a few levels from getting access to Root of Warrior, so just take the defeat for now and try to get level 55 as fast as you can. Also, Kurenai is highly suggested and is very useful in the current meta, so it's not bad to go after her.

A fully skillbroken Kurenai is at S+ tier, just below the god ninjas. It's not too late. Also, about unbound runes, they're good, and you'd probably have enough arena coins to buy both Kurenai and the runes. Once you've gotten her to 4 stars, prioritize breaking her chase talent so it adds chaos effects, that could win you most of your battles + you would already have root of warriors that seals the deal. Remember, for this lineup, it is of utmost importance to solely focus your refine on main LM, cause you will be putting him on the very front.

Sasuke - Kurenai - LM
x - Iruka - x
x - x - x

Also, I'm speaking of this assuming you're going to freeze your level starting 65 or 70. If you level up more than that, that lineup would no longer serve you well, and most of your battles will be hell. So, take it from someone who has done several tests. I'm at level 78 with 57k power, still doing fine, but there's somehow a bit of regret that I decided to level up past 70. I should have stopped at 70 completely.

Well, it did made sense for me and for people like me who had frozen our levels at level 70s, giving us almost 6k initiative on our 1st move ninjas, way more than most whales of our level, and even far more than the mild spenders 5 levels th*. I get to enjoy 1-2nd place in sage each time, constantly gets six paths. Constant 5 wins in matsuri, etc. What doesn't make sense is your comment, and you're merely basing on your own narrow experience, no matter how long you think you've been playing. Unless you can stop us now from the victories we earn, then we might see how freezing our levels no longer make sense.

So what gives you the idea why freezing our level at 70s don't make sense inspite of the favorable results we are having now? Perhaps if we start to rephrase our statements and make sound arguments, that would better address the OP's plead for help. You are advising him to level up further when in fact it would just make the difficulty exponentially worse. And I don't think mine is in a relatively new cluster, it's roughly 5 months old and have been opened for cross-server SWB, arena and matsuri since server opening. While you have a point that if I keep encouraging these new people to freeze their level altogether, they might just end up facing each other. It's up to them and how they use their resources really. Still doesn't change the fact that I just did well when I started freezing my level, since it gave me a lot of opportunities to amass power items and resources to further improve my stats.