If its up around level 80 it wont get beaten, unless you give it bad moves. take one pokemon along with you though, and a bunch of max revives and full restores if blaziken faints, use the other pokemon, but dont make it do anything, just use it as a stall to use a max revive on blaziken. also take lots of ethers and elixers.
people may think its cheap but if i have blaziken i train my weak guys by equipping the exp share to a weak pokemon and putting it in second position(blaziken in first)and battle the newscrew over and over for great experience.
1.all you have to do is ditch the blaiziken 2.have a friend that has lv 100 pokemon 3.meet up with your gameboys 4.get at least 2 lv 100's 5.make sure they have good moves now you should be able to flog the elite 4. trade them back if your friend won't let you keep them. 1 last thing give blaiziken the exp share it could use the experince.