Sun Tzu’s art of war is a highly recommended read by everyone. While it deals with military strategy, the philosophies can be applied to regular modern life. Combat sports such as MMA and boxing try to make matches as fair as possible with weight classes, rules, and referees. Both participants start at the same time.
When it comes to an environment with no rules, situations can occur at any time. In such situations, one can use surprise attacks when the other person is unaware or in an unfavorable situation. If you cannot gain the upper hand even with those advantages in your favor, then it’s likely that you have messed up badly and you picked the wrong target to mess with.