If it's too difficult, I'd suggest doing other challenges to improve your ability and then come back to it. To this day I haven't beaten like 10 of the Event Challenges in Melee (one's with the endless Pikachus, another's trying to get the Majora's Mask trophy, another's against Dr. Mario and white-outfit Peach who I swear have anvils in their fists). Doesn't bother me that much. I'd just try other areas in the meantime, then eventually go back to it when I'm not ticked off at Dr. Mario and try the challenge again. Given enough effort, eventually you'll get it. And if not, you'll probably have 30 hours accumulated by then that you can use some alternate method (if it exists).