Camping is your best friend in this matchup. Since Diddy's too small to be hit with long-lasting combos, your best bet is to play a hit-and-run style. As long as you have the percent lead, there isn't much of a reason to go in against him. Spacing with well-placed fairs and up/down tilts should be your bread-and-butter. When you do get a combo starter, don't go in too hard (unless their SDI is poor, in which case go ham). Get a couple aerials, then drift away and continue a camp-heavy game. Since Diddy's projectile game is poor, you will find success in staying out of banana range and using bullets. By forcing them to approach, you can then catch them with a powerful combo starter.
Of course, if you don't have percent lead (or the lead is very slight), then you'll have to find a way in. A patient Diddy will not continue to press the advantage, since he plays the matchup just like Bayo does. Your best bet is to keep chipping away at him bit by bit, not getting overly greedy.
Bayonetta
Of course, if you don't have percent lead (or the lead is very slight), then you'll have to find a way in. A patient Diddy will not continue to press the advantage, since he plays the matchup just like Bayo does. Your best bet is to keep chipping away at him bit by bit, not getting overly greedy.