Iarla's Beginner Guide to Punch a Bunch Speedrunning

In order to knock out an opponent as quickly as possible, the key is to learn how to stun lock. The stun feature is where you body shot your opponent to the point where there is a sweating animation, at which point they are susceptible to getting stunned by any kind of punch following. 

STUN LOCKING
In order to stun lock, move the joystick forward left or forward right and hold down the right trigger. Wait for an opening in the opponents guard, such as after a missed strike. When the opening appears, flick the joystick in the opposite direction, and keep throwing these body shots. Once they are stunned, this should leave you a chance to hit some high damage headshots. However, before the stun runs out, begin body shotting them again to drop their stamina, leaving them open to a chain of stun locking.