Lmao! How many times have you tried defeating this guy?!

You say your characters are on 3000hp, Im sure I was the same when I tried defeating him. I had lots of trouble because I didnt know how to use the Al Bhed Potions - I didnt realise Rikku was the only one allowed to use them, when I figured that out - I just made Rikku use the potions almost every turn! Beat him easily

If your really stuck, try reading some Boss Walkthroughs ...

http://db.gamefaqs.com/console/ps2/f...y_x_boss_a.txt

Thats a really good one - Boss 18 Evrae Good Luck!