Pokémon preceded the Digimon virtual pets by about a year.
But that's okay because you shouldn't need to "combat" that steaming pile of argument by this day and age. Anyone who still tries to make the case that one "copied" the other or vice versa is either still in elementary school or just a moron (that's right, I said it) because the franchises are about as different as can possibly be save for the superficial shared elements of lots 'o monsters.
I remember being about 6 years old and complaining that Digimon stole the suffix "mon". I've really grown up since then.