If you start losing, you can close the app, start it again and 'quit' the current match, yugi will still be there and you can play the match again, you can do this as much as you want.
The same goes for Standard Duelists and the Vagabond
cheers
PS: you can do the same trick with Legendary Duelists that spawn in the duel world.
DO NOT try to do the trick against LD at the portal, YOU WILL LOSE ALL THE KEYS YOU'VE SPENT
Anoymous
THANK YOU