Trying to get into a Russian-like mindset (impossible, really, despite my past experience with them), maybe it's just a real life version of the new-in-prison or the Pride-Male trope. He had to be seen to take on the strongest comer to resolidify his power.
Sorry, but I'm gonna stereotype here: Russians just really suck as a collective. We're all ugly, selfish humans, and we're mostly worse in our tribal form, but the Russians are really bottom of the barrel.