The Auron's Bushido

Dragon Fang: You will have it at the beginning of the game

Down+Left+Up+Right+L1+R1+O+X is the combination to perform it.

Shooting Star: Really a good one, Auron runs at one enemy and strike it to
send it out of the battle field. You will have it when you find the Jecht
Sphere after beating Spherimorph in the Macalania Wood.

Triangle+Circle+Square+X+Left+Right+X and good bye to the victim.

Banishing Blade: Nice one here, not only that it deals nice damages but also
that when you use it correctly, Auron will inflict all the breaks(Power,
Armor, Mental and Magic break)to the enemy. You will learn it after finding
Three Jecht Spheres.

Up, L1, Down, R1, Right, Left+Triangle

Tornado: The last one, damages all enemies. You will obtain it by getting all
ten Jecth spheres.

X+Right+R1+Left+L1+Triangle


I'm particularly attracted to banishing blade for this battle. The execution isn't complicated, and it does a lot of damage and inflicts all of the breaks(not sure if you will count them for this battle.) The breaks would GREATLY increase Auron's chances of winning this battle.