On the movie "Crossroads", what is the piece of music that he plays on his guitar?

I don't know that Ralph Macchio's riffs were supposed to be a composed piece of music. I interpreted it as his clical guitar studies helping him to face down the "devil's guitarist" (Steve Vai) when Vai could do only rock riffs. It's a shame it is not included on the soundtrack (which features the guitar work of Ry Cooder). The showdown is referred to as "Cutting Heads", I believe, in the film.