keep yuna behind the.......thing, so she wont get attacked by the slash attack (i havnt played this in ages so i cant remember the name) as it only attacks the front 3 glyphs. Make sure auron has high hp to keep it occupied by attacking. Keep auron ALWAYS on the opposite side of yuna and keep attacking. All overdrives should be full. My team was Wakka, Auron,and yuna.

Wakka - Attack reels!!!!!!!!BOOYAH!
Yuna - Summon, summon, summon, then heal if necesary.
Auron - Attack to keep it facing his way.