You need a special speed for the archers here - with or without acceleration, they must be faster than the opponent - otherwise, nothing will work!!! Or you'll have to cast a force field every turn! And then you can forget about the Disintegration Ray and other spells! ;)
And don't forget a looooooot of mana! That's the main condition for such a battle.
But why, Tanya, the force field lasts for two turns, which means you can use any spell in between ;)