Similar to the PS2 version, the game autosaves.
. They would turn off their consoles, only to return the next day and find every character locked once more. The Saving "Secret" battle stadium don save data
If you are using an emulator, keep your save files in a cloud-synced folder to prevent losing your progress to hardware failure. Similar to the PS2 version, the game autosaves
Saving your Battle Stadium data is a straightforward process. Here's a step-by-step guide: Similar to the PS2 version
The game requires roughly 120KB to 200KB of free space.