Espeon > Mewtwo. Wanna see how? just read the text bellow, stats mean nothing if you can't use them correctly.
Mewtwo does a random attack.
Espeon uses Wish.
Mewtwo repeats.
Espeon uses Toxic, Mewtwo was poisoned.
Wish kicks in.
Mewtwo repeats, Mewtwo loses HP from toxic.
Espeon uses Wish
Espeon uses Protect
Mewtwo's repeats, Mewtwo loses more HP from Toxic.
Wish kicks in.
This keep happening over and over and over, Mewtwo tries to Recover, but faints from the doubling effect of Toxic. Good game Mewtwo.