Head Ball 2 always tries to find an equal opponent for you. To do this the system first checks your account level and your average success in Head Ball 2. As a result of these parameters, it will pair you with the most suitable opponent.
At the beginning, your opponents can be up to 2 levels higher than you but this limit increases as you level up. For example, if you are level 35, it will look for the players in +/- 5 level range. In this case, your opponent will be a player between 30 and 40.
Level 1-11: +-2
Level 12-20: +-3
Level 21-30: +-4
Level 31-40: +-5
Level 41-50: +-7
If you are constantly winning your matches, you are likely to be matched with an opponent that is stronger or equivalent to your strength. If the system cannot pair you with a real player, you will be paired with a bot that meets your criteria.
You can defeat tough opponents by upgrading your characters, using super powers, or even better accessories.