I liked the battle, although a bit more description could have been put into the actual attacks. Instead of saying:
You could have said:
Magneton began to gather up electrical surges in each part of its tri-metallic body. When it knew that it had stored maximum capacity, it unleashed them in a great Thunderbolt attack that headed straight for the opponent Metagross.
It's longer, and it would take more time, but it does really improve the quality of the fic, when you alter little details like that. Nothing much to say, really, everything else seems to be in order. Keep up the good work. :D