I am using mega beedrill as I like playing with Pokemon that dont really get used. Mega beedrill with a jolly nature and full EVs in speed has 427 speed. I mega evolved first turn and was sweeped by a gengar 1st turn. I know this Gengar did not have a scarf because it was on 1 HP with Focus Sash. Why wasnt my beedrill faster?
That is why your Beedrill wad outsped and killed.