How do you win the platamie match in kingdom hearts 1

It is extremely hard but possible, I've beaten it and i was only level 60+. Number 1 tip. BRING LOTS OF ELIXIRS!!! Sephiroth has a move that leaves you with 1 hp and no MP so when he's starting to use it, get ready to use an elixir. Other than that, practice. You'll learn his moves how to dodge them, and what signs or patterns he follows before he uses a move. An example is right before he uses the HP MP drain moves, he's flying in the air with spheres surrounding him. Hope this helped.