A special load balancer program is engaged in the selection of rivals. It selects your opponents considering a variety of game parameters. One of them is your senior tank in the hangar. Depending on your experience of playing on it (the number of battle, the number of opponents killed), opponents are selected for you. The more you play, the stronger your opponents, respectively. If, for example, you go into battle on a level 4 tank, and you have a level 8 tank in the hangar, then the opponents will be selected in accordance with the senior tank.