Challenge description:
http://www.femlob.com/redir/ff10nsgnsno/

This is where Tidus' "Lightning Steel" comes in handy. As you can see, I got both lucky and unlucky back-to-back; I managed to Slow him on my first turn, and then came one turn short in forcing him to descend. I could've avoided that by manipulating the turn bar or resetting, but since Extractor's Slow gave Wakka another turn after it descended it didn't matter.

I guess you could call it luck that Wakka didn't get afflicted with Darkness, but I would've just removed that with an Eye Drop on the next turn.