The Iosif Stalin (IS-2) tank, designated as a heavy break-through tank, was ideally suited for the role of leading a spearhead, but hordes of T-34s were also frequently used. These tanks would punch through the German lines and keep going.
Suddenly they have enemy units getting side or rear shots to their own vehicles, or who are moving into position to assault their vulnerable backline assets like mortar teams and artillery pieces. They are forced to press on to their own objectives and ignore your marauding units or divert units to counter them, thus slowing their own attack. This style tactic can be very helpful when you're defending in Point Defence or similar missions, although it can come with risks.
So the next time you manage to create a hole in your opponents line, try flooding through and attacking his backline; cause them to have to completely alter their plans. It worked for the Soviets!