I find overdrives work better. I use my three best characters, (in this case Auron, Wakka and Tidus), protect on everybody, hastega, have everyone's overdrive mode set on ally, and just keep hitting defend. With triple overdrive, it'll take two seconds for everybody to get a third of their overdrive bar, Entrust everything to Wakka and then Attack Reels him into next week.

Serve on a bed of fresh rice or pasta. Enjoy!