The significance of what happened in Rubizhne is that the Russians were stalled as they were trying to advance south through the city itself. But then they outflanked the Ukrainian positions by advancing through the forest to the east of the city. It's that maneuver which set up the battles for Zarya and Vojevodivka. Those were not low-level skirmishes; they took multiple days to play out and involved heavy artillery strikes.
It appears the Chechens are the most combat effective units in the Ukrainian civil war on both sides. Chechens are deeply religious and scare the bejezus out of Ukrainian soldiers the same way Islamist rebels scare the bejezus out of Syrian soldiers.