Mega Altaria
☆~Shiny hunter▢~
Yeah I don't expect Pikachu vs Mimikyu to last for more than a few seconds, before some interruption happens.
But seriously though, I can't believe what I'm reading that just because Pikachu hasn't had a clean victory over Mimikyu so far in this series, that must mean Mimikyu is at par with Pikachu, which is dumb as heck. First of all, all the Pikachu vs Mimikyu encounters have been played for gags, since Mimikyu's hatred of Pikachu boosts its power, and Pikachu is always shocked and surprised to see Mimikyu. Also not to mention, Ash vs TRio has been rare this series, so we rarely get to see them battling. But I'm sure if comes down to a serious battle between Jessie and Ash, and Pikachu is allowed to battle optimally like he would against anyone else, it's bye bye Mimikyu, even with all its stupid hatred. A fully powered Iron Tail to its face will destroy Mimikyu's hatred and send it cowering in fear the next time it meets Pikachu.
Yeah I could see Mimikyu starting to fear Pikachu once it has been properly defeated by Pikachu or even get closer to Pikachu like a usual Mimikyu but I personally don't really get its hatred with Pikachu because Mimikyu will usually try to get closer to other Pokémon.