A schmo from Ordinaryville is The Ace in fantasyland.
"I don't mean to rain on your parade, but we both know that an expert is someone from off-planet with a briefcase." -- Colonel BattleaxeMeet Mike Johnson. He's an ordinary kid from an ordinary town with a paper route and trouble talking to the girl he likes. He has a dog and a bedroom and a haircut. He seems destined to grow up, go to refrigerator repair school, get married, and never leave the humble town of Everyburg. Then Mike gets magically whisked off to Magical Land! He meets elves and fights ogres. He has no frickin' clue how magic works and the social rules and local government are a complete mystery, but thanks to his ability ride a bike and an understanding of how a ground rule double works, he can solve every single problem that has plagued these unwashed heathens for the last five thousand years and rule over them like unto a god. He is... The Wizard From Ordinaryville. The original Trope Namer was The Wizard of Oz. A travelling carny from Omaha with a penchant for fake magic gets whisked away in his hot air balloon to a land of real magic and ends up ruling there as an unquestioned tyrant, the Great and Powerful Oz. Unlike a Normal Fish in a Tiny Pond, where the protagonist possesses a power that makes him unique in Magical Land, The Wizard didn't stand out in Ordinaryville and stands out even less in Fantasyland. Compare to Summon Everyman Hero, where it's explicitly stated that The Everyman is exactly what Magical Land needs, and Down the Rabbit Hole. May have Unfortunate Implications of the Mighty Whitey type.