Level up some more if you can. Equip clearheaded if you have it. Use a tent on it at the beginning at the fight.(If it works, it will help a lot!) Have freya use jump a lot, if she has Reises Wind(or however you spell it, use it at the beginning. . Have Zidane takes turns through steal and attacking. Throw some stuff at him with Amarant and keep attacking, heal when needed. That's how I beat it!