Item: choice scarf
Nature: Adamant or Jolly
EV's: 252 Atk, 252 Spd, 4 Hp
Moveset: Superpower, Night slash, Switcheroo, Topsyturvy
Choice scarf gives Malamar speed over most unboosted Pokemon.
Using the contrary ability, just keep spamming superpower for good damage and the Attack and defense boost every turn.(worth useing some pp ups on super power). If you get outsped Malamar has average defenses and should be able to sustain a neutral hit.
Switch in to a swords dancing or calm minding opponent and use Switcheroo to get them stuck boosting them self with thy choice scarf. Then you can use Topsyturvy or dish out some damage with superpower and night slash.