Deadliest Warrior

I struggled getting this (I think it was because I was using two x 3 button combos, meaning they would be dead before I connected with the last hit on the second combo)

In the end I used the Samurai first used the X,Y,A combo and then followed it up with the X,X combo and the achievement popped up.

My opponent was the Apache.

I got this by doing the Y+X+B combo with the pirate. With upgraded weapons, the first two parts of the combo do some damage, and the bunderbus shot at the end will kill (close range shot). One combo, timed and executed to a death.
I did this in arcade, but I'm sure it'll be easier if you just got a two-player game with a 'stand still' opponent.

This achievement will come naturally. I got it on by third game. How I got it was by killing by opponent without missing a hit, none of my hits were blocked, and I received a perfect, or no damage done to me, for the round. If you cannot get it by yourself, get a friend to help you online or login to local multilayer with another controller and get it that way.

If you still need help, message me or leave a comment and I would be glad to help.

Kane M.