Well,on the event stage lvl. 51 I took you're advice... But it dident work.i..

I found Falco to be a great character for this event. But there isn't really a strategy other than the Jigglypuff one. Sorry.

Try my Yoshi strategy.

Kill giga bowser first then go for gannondorf.Mew2 is the easiest.

Well, I happened to use Fox, and I ended up winning...

I used to be a master of this game, no one could beat me except the line guys on cruel melee and the people in Event 51. But I found a way to beat it even though it was hard. Use the down-B button to kill giga bowser and only use it for Mewtwo and Ganandorf if you're sure it's going to work. Mewtwo I can't help you there but for Ganandorf, keep hitting him with the normal attack button and the special attack button, also if you jump and he does that up-B attack press down-A quickly to stop him. This may not help you a lot though, and if it dosn't help at all, I'm sorry

Hey - a RAMPAGE might work, that's a good idea - try doing that (while playing the Event Match); but no, there isn't a 'flawless strategy' sorry...
Keep trying McDonalds!!!

I did it with jigglypuff and after you beat giga bowser just fly from side to side and wait for items to appear. Make sure you get high enough before you start moving to the other side or ganondorf will use his up-B on you. You could also try young link just keep using up-B and when they get a lot of damage use A.
Peace.

Use who youre good with. me I personally like roy and I beat them easiliy

I thought it was "impossible too, but how I comlpeted it is:

I used Captian Falcon for this one. When the battle starts, I keep using his forward+A smash attack (something that looks like a knee bash) on Giga Bowser. Eventually, you can get him over 100% damage, and knock him offstage (I recommend that if you lose 2 lives before KO'ing him his 3 lives, then to press start, and then press "Z" to restart the match). With Mewtwo and Gannondorf left, I keep using the Falco Punch, until I lose a life. Then, of course, I only have one left. At this point, I just jump from one side of the field to the other, until a good item appears (pokeball, motion-sensor bomb, red shell or green shell). Sometimes a bob-omb will appear. Just keep jumping from one side of the field to the other, and it will eventually explode Mewtwo or Gannondorf (or maybe both. [Just try not to land on it, like I did. There were like 6 bob-ombs all over the field, and it was just me and Gannondorf left, both of us with one life left, and "I" just happened to run into one, and that annoying "Failure" thing appeared. I couldn't believe it!! I could've had it right there, but nooooo... They just had to make it run into me instead of him!! "WHAT THE F**K!!", I shouted at that time.]) Enough of that, and back to the strategy... Other Items may appear,but just forget about them. With practice and luck, you will get it. (I got super lucky when I beat it. It was just me and Gannondorf left. We both had over 100% damage, and a pokeball appeared. I rushed over and got it. A Togepi appeared, and smashed Gannondorf into the ground [like what one of Donkey Kong's smash attacks does] and he couldn't attack or anything. So, without wasting a second, I ran over and pressed "B"........FALCO PUNCH!!!!!!! Captian Falcon said, and then that sent Gannondorf flying into the sky and winning me the match with a star KO...after working on it for like 3 days for about 6 to 8 hours on each of those days!! MAN!! I couldn't believe I finally got it!! It was the best moment of the game I ever experienced!! I remember it like it was yesterday...BECAUSE IT WAS!! Well, hopefully you can complete this faster than I did, but even if you don't, within the next few battles...give it time, and eventually you will have my kind of luck After you beat it, you unlock a few things, which I won't tell you. You can find out 2 ways: Cheat and look online, or don't cheat and find out for yourself. Before I make this longer than it already is, since I have a habit of going on, and on, and on, and... ... About stuff like this,I will end it here by saying...

GOOD LUCK!!