This is an attack first move.
A pokemon using an attack first move will go before the opposing pokemon unless the opponent is also using an attack first move or a protection move (Detect, Endure, Protect). If the opponent is also using an attack first move then the pokemon with the higher speed will go first, as per usual.
An attack first move will go first even if selected when a pokemon is Asleep or Frozen, which can end up in opponents performing a Sleep round first for no apparent reason (it can also be a way out of a sleep trap when combined with Brightpowder, if anyone used sleep traps anymore).
Mach Punch receives the flinching bonus when King's Rock is attached to the using pokémon.
Mach Punch is affected by Brightpowder when the opposing pokémon is equipped with it.
Attack first moves include: Extremespeed, Mach Punch, and Quick Attack.
