This is a tier 5 tank, therefore being able to play in Supremacy. It has decent armor, but has no turret, like most Tank Destroyers.
This tank is used for penetrating heavy tanks, so find a location to snipe the enemy tanks. Do not ever go into close combat, as you have slow turning speed. Stay clear of open areas and always use sniper mode to attack.
Try to surround the SU-85, so that it is confused on who to hit. Try to sneak up on it so you gain get a high advantage. It has slow reload, so get a bunch of allies to shoot it. If you are targeted, run for help in a zigzag pattern.