Reborn in inazuma eleven and remembering my past life

What if someone from our world was reborn in inazuma eleven but didn't remember anything until after the game between royal and raimon?

what if he changed some things by getting a lot stronger and making his own training up? what if he built his training equipment and used it a lot? what if when he and everyone else saw improvement in him, he decided to finally show his team what training his been using while his team was going to ask what he's been doing to improve a whole lot in two days.
who knew that he had his own underground base in his own house?

(changes in different things, personality might be included in changes)