"Pi-pikachu ka pika ka! Chu chu pika-pikachu pi pi pi ka chu ka pik chu. Ka pikachu pikachu pi pi kachu. Pika pikachu pi- pi pikachu":

(Translation:"Now for Event Matches! Only the first 10 event matches are available at the start. The others must be unlocked. Here are the unlocks":)

Event matches 11 - 15: Win 6 different matches from events 1 - 10

Event matches 16 - 20: Win 10 different matches from events 1 - 15

Event matches 21 - 25: Win 16 different matches from events 1 - 20

Event matches 26 - 29: Win 22 different matches from events 1 - 25

Event match 30: Win 27 different matches from events 1 - 29

Event matches 31 - 39: Win all 30  matches from events 1 - 30 and unlock 4 specific hidden characters(I dont know which ones).

Event matches 40 - 50: Win 30 different matches from events 1 - 39 and unlock all characters except Mr. Game and Watch and Pichu.

Event match 51: Win all 50 event matches and defeat Giga Bowser in adventure mode.

Have fun unlocking!