I have beaten several other master trainers without much trouble but the Beedrill one I cannot beat. Im higher level than him and can mega evolve but lose miserably each time. Please help! I dont know what I'm doing wrong!
Feed candies to Beedrill that increase its speed. You'll also want to teach your Beedrill Outrage or Drill Run if you have their TMs. Both standard and Mega Beedrill have pretty poor bulk overall, so you should be able to quickly beat it provided you can outspeed it.