Welcome to Smogon! Take a moment to read the Introduction to Smogon for a run-down on everything Smogon, and make sure you take some time to read the global rules.
Just to be sure, the same rules that apply to tie breakers with the last Pokémon are also applied here, isn't it? For example, if I use Explosion first turn, I lose, even if I KO at least one of the opponents Pokémon, isn't it?