I got really lucky with this fight. After the 4th gym I pretty much only used Haxorus, that was lvl 95, rest around 50-60. First try Deoxys destroyed my entire team in one shot each. I tried EV training my Haxorus' Sp Def hoping it would survive one ice beam, it didn't. After 5 pokemon died I only had my Sturdy Aggron left. Deoxys used an attack with a 70% accuracy so I kept restoring health to get sturdy back hoping it would miss giving me a chance to do some damage. After using my last potion it missed for the 3rd time and I finally took it down with a critical hit :D Was certainly a pricey fight, 2 geodudes would have been much easier:P