(Haha I get to discuss my two mains :D)
I think this is a pretty even matchup maybe 55:45 diddy at the most...
Onstage:
Diddy has the great advantage ONLY IF HE HAS BOTH BANANAS,.. Stay airborn, for those who don't know diddy is not very good at fighting characters with multiple jumps (jigglypuff is an even matchup O.o). Watch where u land tho... try not to be shooting an arrow on ur last jump (diddys punish landing lag)... watch for peanuts their amazing for zoning and setting up combos... if diddy has a wall of peanuts and 2 bananas... DO NOT APPROACH... arrow em to approach... Dthrow n Uthrow r important in this matchup... as diddy's dair is amazing but not when it comes to getting outta a juggle it fails..
diddy is all about sheild pressure... try not to get caught up on the ground stuck in sheild... it screams a combo or diddy hump... if diddy is obvious with his foward gt... downB or sideB that crapp...
Watch his movement when he's tryn to setup bananas or get one he throw short of u... he sometimes will expect u to go for it or sh over it... he can sh fair to punish jumping around, and idk its a bit mindgamey... but the main point is to throw off his banana control... if diddy loses banana control he loses stage control...
For pits that don't know how to play with bananas tbh u shud really learn the basic at's (I will show a few that r key to fight against diddy)
-sheild bouncing (when diddy throws a banana u sheild it, it will pop up a bit u jump and catch with z (grab button)]
-glidetossing (banana in hand...sheild/roll... at the startup with ur roll throw banana with a (quicker, shorter throw in direction of roll) or c stick (a teeny bit slower, longer throw in direction of cstick)...
U can glidetoss and combo out of it like fsmash,dsmash or whatever... its very useful
Instant throw (airdodge > a... I set my attack button to L for this AT... its very fast timing but easy.... it pretty much catches n throws the banana right back... amazing at )
Mess around with them they r quite useful...
Airgame: its really close pits airiels are alright but watch diddy's fair.. its fast lots of knockbak.... stay defenseive in air... use ur jumps wisely... don't do something that might be risky, ... just be pacient and watch diddys movement that's how ull get round him... but. Id say its evenish...
Offstage... pit wins, get diddy offstage and arrowgimp... he will attemp to side b ledge alot... intercept em... force rocket barrels... and just do whatever to gimp him... when ur offstage just arrow and make it bak to the stage... watch for diddys mix'ups. He will fair or dair on occasion... bananas being thrown and peanutss [if u get forced to up b be on ur toes like always]...
Oh and if diddy is off edge and he's charging barrles right perpendicular below and u have a banana... jumpoff and dthrow banana.... its an easy k.o. (n commonsense]
So yea... tbh its winnable... I beat diddys in some friendlies last week with pit...
Ban PS1 or yoshi's imo... diddy is good there and u can't recover as well for obvious reasons... Take Diddy brinstar or RC... Diddy is realy good on the boat on RC so play passive there... Brinstar is eh... a good diddy can abuse that stage and camp with a banana bouncing on those gay fungus things with peanuts... oh and just an fyi a good diddy can rocketbarrel spike u thru stage ;]
55:45diddy.... but its alright
(This is all my opinion cuz of my diddy knowledge but I lack matchup exp but I know diddy and pit pretty well. It was my 1st tourny in a while and I super improved.... I also decieded imma diddy/pit at tournys cuz my pit is actually decent.. :D)