I always thought the devil won, not because of the music but because Johnny made a deal with the devil. Johnny corrupted his own soul. Also Johnny was pretty Prideful. “My Name’s Johnny and it might be a sin, but I’ll take your be, your gonna regreat, Cause I’m the best that’s ever been.” Heh.
The devil going to get Johnny’s’ soul, but just not right then.
Even if you think the devil played better than Johnny, the devil thought that Johnny played better.
“The devil bowed his head, because he knew that he’d been beat.”
Or it could be the devil is messing with Johnny, since he is going to get the boy’s soul anyway.